x/auction: audit revisions (#497)

Auction audit revisions
2024-11-10 10:05:18 +00:00 · 2020-05-13 09:31:36 -04:00 · 2020-05-13 09:31:36 -04:00 · 6dedc1520a
commit 6dedc1520a
parent 12fe0c60a3 f0c750cb4a
16 changed files with 329 additions and 322 deletions
--- a/x/auction/alias.go
+++ b/x/auction/alias.go
@ -1,109 +1,105 @@
 package auction

+// DO NOT EDIT - generated by aliasgen tool (github.com/rhuairahrighairidh/aliasgen)
+
 import (
 	"github.com/kava-labs/kava/x/auction/keeper"
 	"github.com/kava-labs/kava/x/auction/types"
 )

-// nolint
-// autogenerated code using github.com/rigelrozanski/multitool
-// aliases generated for the following subdirectories:
-// ALIASGEN: github.com/kava-labs/kava/x/auction/keeper
-// ALIASGEN: github.com/kava-labs/kava/x/auction/types
-
 const (
-	EventTypeAuctionStart     = types.EventTypeAuctionStart
-	EventTypeAuctionBid       = types.EventTypeAuctionBid
-	EventTypeAuctionClose     = types.EventTypeAuctionClose
-	AttributeValueCategory    = types.AttributeValueCategory
 	AttributeKeyAuctionID     = types.AttributeKeyAuctionID
 	AttributeKeyAuctionType   = types.AttributeKeyAuctionType
+	AttributeKeyBid           = types.AttributeKeyBid
 	AttributeKeyBidder        = types.AttributeKeyBidder
-	AttributeKeyBidDenom      = types.AttributeKeyBidDenom
-	AttributeKeyLotDenom      = types.AttributeKeyLotDenom
-	AttributeKeyBidAmount     = types.AttributeKeyBidAmount
-	AttributeKeyLotAmount     = types.AttributeKeyLotAmount
+	AttributeKeyCloseBlock    = types.AttributeKeyCloseBlock
 	AttributeKeyEndTime       = types.AttributeKeyEndTime
-	DefaultNextAuctionID      = types.DefaultNextAuctionID
-	ModuleName                = types.ModuleName
-	StoreKey                  = types.StoreKey
-	RouterKey                 = types.RouterKey
-	DefaultParamspace         = types.DefaultParamspace
-	QuerierRoute              = types.QuerierRoute
-	DefaultMaxAuctionDuration = types.DefaultMaxAuctionDuration
+	AttributeKeyLot           = types.AttributeKeyLot
+	AttributeKeyMaxBid        = types.AttributeKeyMaxBid
+	AttributeValueCategory    = types.AttributeValueCategory
 	DefaultBidDuration        = types.DefaultBidDuration
+	DefaultMaxAuctionDuration = types.DefaultMaxAuctionDuration
+	DefaultNextAuctionID      = types.DefaultNextAuctionID
+	DefaultParamspace         = types.DefaultParamspace
+	EventTypeAuctionBid       = types.EventTypeAuctionBid
+	EventTypeAuctionClose     = types.EventTypeAuctionClose
+	EventTypeAuctionStart     = types.EventTypeAuctionStart
+	ModuleName                = types.ModuleName
+	QuerierRoute              = types.QuerierRoute
 	QueryGetAuction           = types.QueryGetAuction
 	QueryGetAuctions          = types.QueryGetAuctions
 	QueryGetParams            = types.QueryGetParams
+	RouterKey                 = types.RouterKey
+	StoreKey                  = types.StoreKey
 )

 var (
-	// functions aliases
-	NewKeeper                            = keeper.NewKeeper
-	NewQuerier                           = keeper.NewQuerier
-	RegisterInvariants                   = keeper.RegisterInvariants
-	NewSurplusAuction                    = types.NewSurplusAuction
-	NewDebtAuction                       = types.NewDebtAuction
-	NewCollateralAuction                 = types.NewCollateralAuction
-	NewWeightedAddresses                 = types.NewWeightedAddresses
-	RegisterCodec                        = types.RegisterCodec
-	ErrInvalidInitialAuctionID           = types.ErrInvalidInitialAuctionID
-	ErrInvalidModulePermissions          = types.ErrInvalidModulePermissions
-	ErrUnrecognizedAuctionType           = types.ErrUnrecognizedAuctionType
-	ErrAuctionNotFound                   = types.ErrAuctionNotFound
-	ErrAuctionHasNotExpired              = types.ErrAuctionHasNotExpired
-	ErrAuctionHasExpired                 = types.ErrAuctionHasExpired
-	ErrInvalidBidDenom                   = types.ErrInvalidBidDenom
-	ErrInvalidLotDenom                   = types.ErrInvalidLotDenom
-	ErrBidTooSmall                       = types.ErrBidTooSmall
-	ErrBidTooLarge                       = types.ErrBidTooLarge
-	ErrLotTooSmall                       = types.ErrLotTooSmall
-	ErrLotTooLarge                       = types.ErrLotTooLarge
-	ErrCollateralAuctionIsInReversePhase = types.ErrCollateralAuctionIsInReversePhase
-	ErrCollateralAuctionIsInForwardPhase = types.ErrCollateralAuctionIsInForwardPhase
-	NewGenesisState                      = types.NewGenesisState
-	DefaultGenesisState                  = types.DefaultGenesisState
-	GetAuctionKey                        = types.GetAuctionKey
-	GetAuctionByTimeKey                  = types.GetAuctionByTimeKey
-	Uint64ToBytes                        = types.Uint64ToBytes
-	Uint64FromBytes                      = types.Uint64FromBytes
-	NewMsgPlaceBid                       = types.NewMsgPlaceBid
-	NewParams                            = types.NewParams
-	DefaultParams                        = types.DefaultParams
-	ParamKeyTable                        = types.ParamKeyTable
-	NewQueryAllAuctionParams             = types.NewQueryAllAuctionParams
-	NewAuctionWithPhase                  = types.NewAuctionWithPhase
+	// function aliases
+	ModuleAccountInvariants  = keeper.ModuleAccountInvariants
+	NewKeeper                = keeper.NewKeeper
+	NewQuerier               = keeper.NewQuerier
+	RegisterInvariants       = keeper.RegisterInvariants
+	ValidAuctionInvariant    = keeper.ValidAuctionInvariant
+	ValidIndexInvariant      = keeper.ValidIndexInvariant
+	DefaultGenesisState      = types.DefaultGenesisState
+	DefaultParams            = types.DefaultParams
+	GetAuctionByTimeKey      = types.GetAuctionByTimeKey
+	GetAuctionKey            = types.GetAuctionKey
+	NewAuctionWithPhase      = types.NewAuctionWithPhase
+	NewCollateralAuction     = types.NewCollateralAuction
+	NewDebtAuction           = types.NewDebtAuction
+	NewGenesisState          = types.NewGenesisState
+	NewMsgPlaceBid           = types.NewMsgPlaceBid
+	NewParams                = types.NewParams
+	NewQueryAllAuctionParams = types.NewQueryAllAuctionParams
+	NewSurplusAuction        = types.NewSurplusAuction
+	NewWeightedAddresses     = types.NewWeightedAddresses
+	ParamKeyTable            = types.ParamKeyTable
+	RegisterCodec            = types.RegisterCodec
+	Uint64FromBytes          = types.Uint64FromBytes
+	Uint64ToBytes            = types.Uint64ToBytes

 	// variable aliases
-	DistantFuture          = types.DistantFuture
-	ModuleCdc              = types.ModuleCdc
-	AuctionKeyPrefix       = types.AuctionKeyPrefix
-	AuctionByTimeKeyPrefix = types.AuctionByTimeKeyPrefix
-	NextAuctionIDKey       = types.NextAuctionIDKey
-	DefaultIncrement       = types.DefaultIncrement
-	KeyBidDuration         = types.KeyBidDuration
-	KeyMaxAuctionDuration  = types.KeyMaxAuctionDuration
-	KeyIncrementSurplus    = types.KeyIncrementSurplus
-	KeyIncrementDebt       = types.KeyIncrementDebt
-	KeyIncrementCollateral = types.KeyIncrementCollateral
+	AuctionByTimeKeyPrefix     = types.AuctionByTimeKeyPrefix
+	AuctionKeyPrefix           = types.AuctionKeyPrefix
+	DefaultIncrement           = types.DefaultIncrement
+	DistantFuture              = types.DistantFuture
+	ErrAuctionHasExpired       = types.ErrAuctionHasExpired
+	ErrAuctionHasNotExpired    = types.ErrAuctionHasNotExpired
+	ErrAuctionNotFound         = types.ErrAuctionNotFound
+	ErrBidTooLarge             = types.ErrBidTooLarge
+	ErrBidTooSmall             = types.ErrBidTooSmall
+	ErrInvalidBidDenom         = types.ErrInvalidBidDenom
+	ErrInvalidInitialAuctionID = types.ErrInvalidInitialAuctionID
+	ErrInvalidLotDenom         = types.ErrInvalidLotDenom
+	ErrLotTooLarge             = types.ErrLotTooLarge
+	ErrLotTooSmall             = types.ErrLotTooSmall
+	ErrUnrecognizedAuctionType = types.ErrUnrecognizedAuctionType
+	KeyBidDuration             = types.KeyBidDuration
+	KeyIncrementCollateral     = types.KeyIncrementCollateral
+	KeyIncrementDebt           = types.KeyIncrementDebt
+	KeyIncrementSurplus        = types.KeyIncrementSurplus
+	KeyMaxAuctionDuration      = types.KeyMaxAuctionDuration
+	ModuleCdc                  = types.ModuleCdc
+	NextAuctionIDKey           = types.NextAuctionIDKey
 )

 type (
 	Keeper                = keeper.Keeper
 	Auction               = types.Auction
+	AuctionWithPhase      = types.AuctionWithPhase
 	Auctions              = types.Auctions
 	BaseAuction           = types.BaseAuction
-	SurplusAuction        = types.SurplusAuction
-	DebtAuction           = types.DebtAuction
 	CollateralAuction     = types.CollateralAuction
-	WeightedAddresses     = types.WeightedAddresses
-	SupplyKeeper          = types.SupplyKeeper
+	DebtAuction           = types.DebtAuction
 	GenesisAuction        = types.GenesisAuction
 	GenesisAuctions       = types.GenesisAuctions
 	GenesisState          = types.GenesisState
 	MsgPlaceBid           = types.MsgPlaceBid
 	Params                = types.Params
-	QueryAuctionParams    = types.QueryAuctionParams
 	QueryAllAuctionParams = types.QueryAllAuctionParams
-	AuctionWithPhase      = types.AuctionWithPhase
+	QueryAuctionParams    = types.QueryAuctionParams
+	SupplyKeeper          = types.SupplyKeeper
+	SurplusAuction        = types.SurplusAuction
+	WeightedAddresses     = types.WeightedAddresses
 )
--- a/x/auction/genesis_test.go
+++ b/x/auction/genesis_test.go
@ -9,17 +9,20 @@ import (

 	abci "github.com/tendermint/tendermint/abci/types"

+	sdk "github.com/cosmos/cosmos-sdk/types"
+
 	"github.com/kava-labs/kava/app"
 	"github.com/kava-labs/kava/x/auction"
 )

+var _, testAddrs = app.GeneratePrivKeyAddressPairs(2)
 var testTime = time.Date(1998, 1, 1, 0, 0, 0, 0, time.UTC)
 var testAuction = auction.NewCollateralAuction(
 	"seller",
 	c("lotdenom", 10),
 	testTime,
 	c("biddenom", 1000),
-	auction.WeightedAddresses{},
+	auction.WeightedAddresses{Addresses: testAddrs, Weights: []sdk.Int{sdk.OneInt(), sdk.OneInt()}},
 	c("debt", 1000),
 ).WithID(3).(auction.GenesisAuction)

--- a/x/auction/keeper/auctions.go
+++ b/x/auction/keeper/auctions.go
@ -20,6 +20,7 @@ func (k Keeper) StartSurplusAuction(ctx sdk.Context, seller string, lot sdk.Coin
 		types.DistantFuture,
 	)

+	// NOTE: for the duration of the auction the auction module account holds the lot
 	err := k.supplyKeeper.SendCoinsFromModuleToModule(ctx, seller, types.ModuleName, sdk.NewCoins(lot))
 	if err != nil {
 		return 0, err
@ -35,8 +36,8 @@ func (k Keeper) StartSurplusAuction(ctx sdk.Context, seller string, lot sdk.Coin
 			types.EventTypeAuctionStart,
 			sdk.NewAttribute(types.AttributeKeyAuctionID, fmt.Sprintf("%d", auction.GetID())),
 			sdk.NewAttribute(types.AttributeKeyAuctionType, auction.GetType()),
-			sdk.NewAttribute(types.AttributeKeyBidDenom, auction.Bid.Denom),
-			sdk.NewAttribute(types.AttributeKeyLotDenom, auction.Lot.Denom),
+			sdk.NewAttribute(types.AttributeKeyBid, auction.Bid.String()),
+			sdk.NewAttribute(types.AttributeKeyLot, auction.Lot.String()),
 		),
 	)
 	return auctionID, nil
@ -50,14 +51,16 @@ func (k Keeper) StartDebtAuction(ctx sdk.Context, buyer string, bid sdk.Coin, in
 		bid,
 		initialLot,
 		types.DistantFuture,
-		debt)
+		debt,
+	)

 	// This auction type mints coins at close. Need to check module account has minting privileges to avoid potential err in endblocker.
 	macc := k.supplyKeeper.GetModuleAccount(ctx, buyer)
 	if !macc.HasPermission(supply.Minter) {
-		return 0, sdkerrors.Wrap(types.ErrInvalidModulePermissions, supply.Minter)
+		panic(fmt.Errorf("module '%s' does not have '%s' permission", buyer, supply.Minter))
 	}

+	// NOTE: for the duration of the auction the auction module account holds the debt
 	err := k.supplyKeeper.SendCoinsFromModuleToModule(ctx, buyer, types.ModuleName, sdk.NewCoins(debt))
 	if err != nil {
 		return 0, err
@ -73,8 +76,8 @@ func (k Keeper) StartDebtAuction(ctx sdk.Context, buyer string, bid sdk.Coin, in
 			types.EventTypeAuctionStart,
 			sdk.NewAttribute(types.AttributeKeyAuctionID, fmt.Sprintf("%d", auction.GetID())),
 			sdk.NewAttribute(types.AttributeKeyAuctionType, auction.GetType()),
-			sdk.NewAttribute(types.AttributeKeyBidDenom, auction.Bid.Denom),
-			sdk.NewAttribute(types.AttributeKeyLotDenom, auction.Lot.Denom),
+			sdk.NewAttribute(types.AttributeKeyBid, auction.Bid.String()),
+			sdk.NewAttribute(types.AttributeKeyLot, auction.Lot.String()),
 		),
 	)
 	return auctionID, nil
@ -98,6 +101,7 @@ func (k Keeper) StartCollateralAuction(
 		debt,
 	)

+	// NOTE: for the duration of the auction the auction module account holds the debt and the lot
 	err = k.supplyKeeper.SendCoinsFromModuleToModule(ctx, seller, types.ModuleName, sdk.NewCoins(lot))
 	if err != nil {
 		return 0, err
@ -117,8 +121,9 @@ func (k Keeper) StartCollateralAuction(
 			types.EventTypeAuctionStart,
 			sdk.NewAttribute(types.AttributeKeyAuctionID, fmt.Sprintf("%d", auction.GetID())),
 			sdk.NewAttribute(types.AttributeKeyAuctionType, auction.GetType()),
-			sdk.NewAttribute(types.AttributeKeyBidDenom, auction.Bid.Denom),
-			sdk.NewAttribute(types.AttributeKeyLotDenom, auction.Lot.Denom),
+			sdk.NewAttribute(types.AttributeKeyBid, auction.Bid.String()),
+			sdk.NewAttribute(types.AttributeKeyLot, auction.Lot.String()),
+			sdk.NewAttribute(types.AttributeKeyMaxBid, auction.MaxBid.String()),
 		),
 	)
 	return auctionID, nil
@ -218,7 +223,7 @@ func (k Keeper) PlaceBidSurplus(ctx sdk.Context, a types.SurplusAuction, bidder
 			types.EventTypeAuctionBid,
 			sdk.NewAttribute(types.AttributeKeyAuctionID, fmt.Sprintf("%d", a.ID)),
 			sdk.NewAttribute(types.AttributeKeyBidder, a.Bidder.String()),
-			sdk.NewAttribute(types.AttributeKeyBidAmount, a.Bid.Amount.String()),
+			sdk.NewAttribute(types.AttributeKeyBid, a.Bid.String()),
 			sdk.NewAttribute(types.AttributeKeyEndTime, fmt.Sprintf("%d", a.EndTime.Unix())),
 		),
 	)
@ -233,7 +238,7 @@ func (k Keeper) PlaceForwardBidCollateral(ctx sdk.Context, a types.CollateralAuc
 		return a, sdkerrors.Wrapf(types.ErrInvalidBidDenom, "%s ≠ %s", bid.Denom, a.Bid.Denom)
 	}
 	if a.IsReversePhase() {
-		return a, sdkerrors.Wrapf(types.ErrCollateralAuctionIsInReversePhase, "%d", a.ID)
+		panic("cannot place forward bid on auction in reverse phase")
 	}
 	minNewBidAmt := a.Bid.Amount.Add( // new bids must be some % greater than old bid, and at least 1 larger to avoid replacing an old bid at no cost
 		sdk.MaxInt(
@ -294,7 +299,7 @@ func (k Keeper) PlaceForwardBidCollateral(ctx sdk.Context, a types.CollateralAuc
 			types.EventTypeAuctionBid,
 			sdk.NewAttribute(types.AttributeKeyAuctionID, fmt.Sprintf("%d", a.ID)),
 			sdk.NewAttribute(types.AttributeKeyBidder, a.Bidder.String()),
-			sdk.NewAttribute(types.AttributeKeyBidAmount, a.Bid.Amount.String()),
+			sdk.NewAttribute(types.AttributeKeyBid, a.Bid.String()),
 			sdk.NewAttribute(types.AttributeKeyEndTime, fmt.Sprintf("%d", a.EndTime.Unix())),
 		),
 	)
@ -309,7 +314,7 @@ func (k Keeper) PlaceReverseBidCollateral(ctx sdk.Context, a types.CollateralAuc
 		return a, sdkerrors.Wrapf(types.ErrInvalidLotDenom, lot.Denom, a.Lot.Denom)
 	}
 	if !a.IsReversePhase() {
-		return a, sdkerrors.Wrapf(types.ErrCollateralAuctionIsInForwardPhase, "%d", a.ID)
+		panic("cannot place reverse bid on auction in forward phase")
 	}
 	maxNewLotAmt := a.Lot.Amount.Sub( // new lot must be some % less than old lot, and at least 1 smaller to avoid replacing an old bid at no cost
 		sdk.MaxInt(
@ -336,13 +341,18 @@ func (k Keeper) PlaceReverseBidCollateral(ctx sdk.Context, a types.CollateralAuc
 			return a, err
 		}
 	}
+
 	// Decrease in lot is sent to weighted addresses (normally the CDP depositors)
-	// TODO paying out rateably to cdp depositors is vulnerable to errors compounding over multiple bids - check this can't be gamed.
+	// Note: splitting an integer amount across weighted buckets results in small errors.
 	lotPayouts, err := splitCoinIntoWeightedBuckets(a.Lot.Sub(lot), a.LotReturns.Weights)
 	if err != nil {
 		return a, err
 	}
 	for i, payout := range lotPayouts {
+		// if the payout amount is 0, don't send 0 coins
+		if !payout.IsPositive() {
+			continue
+		}
 		err = k.supplyKeeper.SendCoinsFromModuleToAccount(ctx, types.ModuleName, a.LotReturns.Addresses[i], sdk.NewCoins(payout))
 		if err != nil {
 			return a, err
@ -363,7 +373,7 @@ func (k Keeper) PlaceReverseBidCollateral(ctx sdk.Context, a types.CollateralAuc
 			types.EventTypeAuctionBid,
 			sdk.NewAttribute(types.AttributeKeyAuctionID, fmt.Sprintf("%d", a.ID)),
 			sdk.NewAttribute(types.AttributeKeyBidder, a.Bidder.String()),
-			sdk.NewAttribute(types.AttributeKeyLotAmount, a.Lot.Amount.String()),
+			sdk.NewAttribute(types.AttributeKeyLot, a.Lot.String()),
 			sdk.NewAttribute(types.AttributeKeyEndTime, fmt.Sprintf("%d", a.EndTime.Unix())),
 		),
 	)
@ -429,7 +439,7 @@ func (k Keeper) PlaceBidDebt(ctx sdk.Context, a types.DebtAuction, bidder sdk.Ac
 			types.EventTypeAuctionBid,
 			sdk.NewAttribute(types.AttributeKeyAuctionID, fmt.Sprintf("%d", a.ID)),
 			sdk.NewAttribute(types.AttributeKeyBidder, a.Bidder.String()),
-			sdk.NewAttribute(types.AttributeKeyLotAmount, a.Lot.Amount.String()),
+			sdk.NewAttribute(types.AttributeKeyLot, a.Lot.String()),
 			sdk.NewAttribute(types.AttributeKeyEndTime, fmt.Sprintf("%d", a.EndTime.Unix())),
 		),
 	)
@ -473,6 +483,7 @@ func (k Keeper) CloseAuction(ctx sdk.Context, auctionID uint64) error {
 		sdk.NewEvent(
 			types.EventTypeAuctionClose,
 			sdk.NewAttribute(types.AttributeKeyAuctionID, fmt.Sprintf("%d", auction.GetID())),
+			sdk.NewAttribute(types.AttributeKeyCloseBlock, fmt.Sprintf("%d", ctx.BlockHeight())),
 		),
 	)
 	return nil
@ -480,14 +491,17 @@ func (k Keeper) CloseAuction(ctx sdk.Context, auctionID uint64) error {

 // PayoutDebtAuction pays out the proceeds for a debt auction, first minting the coins.
 func (k Keeper) PayoutDebtAuction(ctx sdk.Context, a types.DebtAuction) error {
+	// create the coins that are needed to pay off the debt
 	err := k.supplyKeeper.MintCoins(ctx, a.Initiator, sdk.NewCoins(a.Lot))
 	if err != nil {
-		return err
+		panic(fmt.Errorf("could not mint coins: %w", err))
 	}
+	// send the new coins from the initiator module to the bidder
 	err = k.supplyKeeper.SendCoinsFromModuleToAccount(ctx, a.Initiator, a.Bidder, sdk.NewCoins(a.Lot))
 	if err != nil {
 		return err
 	}
+	// if there is remaining debt, return it to the calling module to manage
 	if a.CorrespondingDebt.IsPositive() {
 		err = k.supplyKeeper.SendCoinsFromModuleToModule(ctx, types.ModuleName, a.Initiator, sdk.NewCoins(a.CorrespondingDebt))
 		if err != nil {
@ -499,6 +513,7 @@ func (k Keeper) PayoutDebtAuction(ctx sdk.Context, a types.DebtAuction) error {

 // PayoutSurplusAuction pays out the proceeds for a surplus auction.
 func (k Keeper) PayoutSurplusAuction(ctx sdk.Context, a types.SurplusAuction) error {
+	// Send the tokens from the auction module account where they are being managed to the bidder who won the auction
 	err := k.supplyKeeper.SendCoinsFromModuleToAccount(ctx, types.ModuleName, a.Bidder, sdk.NewCoins(a.Lot))
 	if err != nil {
 		return err
@ -508,10 +523,13 @@ func (k Keeper) PayoutSurplusAuction(ctx sdk.Context, a types.SurplusAuction) er

 // PayoutCollateralAuction pays out the proceeds for a collateral auction.
 func (k Keeper) PayoutCollateralAuction(ctx sdk.Context, a types.CollateralAuction) error {
+	// Send the tokens from the auction module account where they are being managed to the bidder who won the auction
 	err := k.supplyKeeper.SendCoinsFromModuleToAccount(ctx, types.ModuleName, a.Bidder, sdk.NewCoins(a.Lot))
 	if err != nil {
 		return err
 	}
+
+	// if there is remaining debt after the auction, send it back to the initiating module for management
 	if a.CorrespondingDebt.IsPositive() {
 		err = k.supplyKeeper.SendCoinsFromModuleToModule(ctx, types.ModuleName, a.Initiator, sdk.NewCoins(a.CorrespondingDebt))
 		if err != nil {
@ -547,11 +565,6 @@ func earliestTime(t1, t2 time.Time) time.Time {

 // splitCoinIntoWeightedBuckets divides up some amount of coins according to some weights.
 func splitCoinIntoWeightedBuckets(coin sdk.Coin, buckets []sdk.Int) ([]sdk.Coin, error) {
-	for _, bucket := range buckets {
-		if bucket.IsNegative() {
-			return nil, fmt.Errorf("cannot split %s into bucket with negative weight (%s)", coin.String(), bucket.String())
-		}
-	}
 	amounts := splitIntIntoWeightedBuckets(coin.Amount, buckets)
 	result := make([]sdk.Coin, len(amounts))
 	for i, a := range amounts {
--- a/x/auction/keeper/keeper.go
+++ b/x/auction/keeper/keeper.go
@ -128,7 +128,7 @@ func (k Keeper) DeleteAuction(ctx sdk.Context, auctionID uint64) {
 }

 // InsertIntoByTimeIndex adds an auction ID and end time into the byTime index.
-func (k Keeper) InsertIntoByTimeIndex(ctx sdk.Context, endTime time.Time, auctionID uint64) { // TODO make private, and find way to make tests work
+func (k Keeper) InsertIntoByTimeIndex(ctx sdk.Context, endTime time.Time, auctionID uint64) {
 	store := prefix.NewStore(ctx.KVStore(k.storeKey), types.AuctionByTimeKeyPrefix)
 	store.Set(types.GetAuctionByTimeKey(endTime, auctionID), types.Uint64ToBytes(auctionID))
 }
--- a/x/auction/keeper/math.go
+++ b/x/auction/keeper/math.go
@ -7,41 +7,52 @@ import (
 )

 // splitIntIntoWeightedBuckets divides an initial +ve integer among several buckets in proportion to the buckets' weights
-// It uses the largest remainder method:
-// https://en.wikipedia.org/wiki/Largest_remainder_method
-// see also: https://stackoverflow.com/questions/13483430/how-to-make-rounded-percentages-add-up-to-100
+// It uses the largest remainder method: https://en.wikipedia.org/wiki/Largest_remainder_method
+// See also: https://stackoverflow.com/questions/13483430/how-to-make-rounded-percentages-add-up-to-100
 func splitIntIntoWeightedBuckets(amount sdk.Int, buckets []sdk.Int) []sdk.Int {
-	// TODO ideally change algorithm to work with -ve numbers. Limiting to +ve numbers until them
+	// Limit input to +ve numbers as algorithm hasn't been scoped to work with -ve numbers.
 	if amount.IsNegative() {
 		panic("negative amount")
 	}
+	if len(buckets) < 1 {
+		panic("no buckets")
+	}
 	for _, bucket := range buckets {
 		if bucket.IsNegative() {
 			panic("negative bucket")
 		}
 	}

-	totalWeights := totalInts(buckets...)
+	// 1) Split the amount by weights, recording whole number part and remainder
+
+	totalWeights := totalInts(buckets...)
+	if !totalWeights.IsPositive() {
+		panic("total weights must sum to > 0")
+	}

-	// split amount by weights, recording whole number part and remainder
 	quotients := make([]quoRem, len(buckets))
 	for i := range buckets {
+		// amount * ( weight/total_weight )
 		q := amount.Mul(buckets[i]).Quo(totalWeights)
 		r := amount.Mul(buckets[i]).Mod(totalWeights)
 		quotients[i] = quoRem{index: i, quo: q, rem: r}
 	}

-	// apportion left over to buckets with the highest remainder (to minimize error)
+	// 2) Calculate total left over from remainders, and apportion it to buckets with the highest remainder (to minimize error)
+
+	// sort by decreasing remainder order
 	sort.Slice(quotients, func(i, j int) bool {
-		return quotients[i].rem.GT(quotients[j].rem) // decreasing remainder order
+		return quotients[i].rem.GT(quotients[j].rem)
 	})

+	// calculate total left over from remainders
 	allocated := sdk.ZeroInt()
 	for _, qr := range quotients {
 		allocated = allocated.Add(qr.quo)
 	}
 	leftToAllocate := amount.Sub(allocated)

+	// apportion according to largest remainder
 	results := make([]sdk.Int, len(quotients))
 	for _, qr := range quotients {
 		results[qr.index] = qr.quo
--- a/x/auction/keeper/math_test.go
+++ b/x/auction/keeper/math_test.go
@ -10,19 +10,97 @@ import (

 func TestSplitIntIntoWeightedBuckets(t *testing.T) {
 	testCases := []struct {
-		name    string
-		amount  sdk.Int
-		buckets []sdk.Int
-		want    []sdk.Int
+		name        string
+		amount      sdk.Int
+		buckets     []sdk.Int
+		want        []sdk.Int
+		expectPanic bool
 	}{
-		{"2split1,1", i(2), is(1, 1), is(1, 1)},
-		{"100split1,9", i(100), is(1, 9), is(10, 90)},
-		{"7split1,2", i(7), is(1, 2), is(2, 5)},
-		{"17split1,1,1", i(17), is(1, 1, 1), is(6, 6, 5)},
+		{
+			name:        "0split0",
+			amount:      i(0),
+			buckets:     is(0),
+			expectPanic: true,
+		},
+		{
+			name:        "5splitnil",
+			amount:      i(5),
+			buckets:     is(),
+			expectPanic: true,
+		},
+		{
+			name:        "-2split1,1",
+			amount:      i(-2),
+			buckets:     is(1, 1),
+			expectPanic: true,
+		},
+		{
+			name:        "2split1,-1",
+			amount:      i(2),
+			buckets:     is(1, -1),
+			expectPanic: true,
+		},
+		{
+			name:    "0split0,0,0,1",
+			amount:  i(0),
+			buckets: is(0, 0, 0, 1),
+			want:    is(0, 0, 0, 0),
+		},
+		{
+			name:    "2split1,1",
+			amount:  i(2),
+			buckets: is(1, 1),
+			want:    is(1, 1),
+		},
+		{
+			name:    "100split1,9",
+			amount:  i(100),
+			buckets: is(1, 9),
+			want:    is(10, 90),
+		},
+		{
+			name:    "100split9,1",
+			amount:  i(100),
+			buckets: is(9, 1),
+			want:    is(90, 10),
+		},
+		{
+			name:    "7split1,2",
+			amount:  i(7),
+			buckets: is(1, 2),
+			want:    is(2, 5),
+		},
+		{
+			name:    "17split1,1,1",
+			amount:  i(17),
+			buckets: is(1, 1, 1),
+			want:    is(6, 6, 5),
+		},
+		{
+			name:    "10split1000000,1",
+			amount:  i(10),
+			buckets: is(1000000, 1),
+			want:    is(10, 0),
+		},
+		{
+			name:    "334733353split730777,31547",
+			amount:  i(334733353),
+			buckets: is(730777, 31547),
+			want:    is(320881194, 13852159),
+		},
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			got := splitIntIntoWeightedBuckets(tc.amount, tc.buckets)
+			var got []sdk.Int
+			run := func() {
+				got = splitIntIntoWeightedBuckets(tc.amount, tc.buckets)
+			}
+			if tc.expectPanic {
+				require.Panics(t, run)
+			} else {
+				require.NotPanics(t, run)
+			}
+
 			require.Equal(t, tc.want, got)
 		})
 	}
--- a/x/auction/spec/04_events.md
+++ b/x/auction/spec/04_events.md
@ -4,12 +4,13 @@ The `x/auction` module emits the following events:

 ## Triggered By Other Modules

-| Type          | Attribute Key | Attribute Value     |
-|---------------|---------------|---------------------|
-| auction_start | auction_id    | {auction ID}        |
-| auction_start | auction_type  | {auction type}      |
-| auction_start | lot_denom     | {auction lot denom} |
-| auction_start | bid_denom     | {auction bid denom} |
+| Type          | Attribute Key | Attribute Value |
+|---------------|---------------|-----------------|
+| auction_start | auction_id    | {auction ID}    |
+| auction_start | auction_type  | {auction type}  |
+| auction_start | lot           | {coin amount}   |
+| auction_start | bid           | {coin amount}   |
+| auction_start | max_bid       | {coin amount}   |

 ## Handlers

@ -19,8 +20,8 @@ The `x/auction` module emits the following events:
 |-------------|---------------|--------------------|
 | auction_bid | auction_id    | {auction ID}       |
 | auction_bid | bidder        | {latest bidder}    |
-| auction_bid | bid_amount    | {coin amount}      |
-| auction_bid | lot_amount    | {coin amount}      |
+| auction_bid | bid           | {coin amount}      |
+| auction_bid | lot           | {coin amount}      |
 | auction_bid | end_time      | {auction end time} |
 | message     | module        | auction            |
 | message     | sender        | {sender address}   |
@ -30,3 +31,4 @@ The `x/auction` module emits the following events:
 | Type          | Attribute Key | Attribute Value |
 |---------------|---------------|-----------------|
 | auction_close | auction_id    | {auction ID}    |
+| auction_close | close_block   | {block height}  |
--- a/x/auction/types/auctions.go
+++ b/x/auction/types/auctions.go
@ -287,15 +287,23 @@ func NewWeightedAddresses(addrs []sdk.AccAddress, weights []sdk.Int) (WeightedAd
 	return wa, nil
 }

-// Validate checks for that the weights are not negative and that lengths match.
+// Validate checks for that the weights are not negative, not all zero, and the lengths match.
 func (wa WeightedAddresses) Validate() error {
+	if len(wa.Weights) < 1 {
+		return fmt.Errorf("must be at least 1 weighted address")
+	}
 	if len(wa.Addresses) != len(wa.Weights) {
 		return fmt.Errorf("number of addresses doesn't match number of weights, %d ≠ %d", len(wa.Addresses), len(wa.Weights))
 	}
+	totalWeight := sdk.ZeroInt()
 	for _, w := range wa.Weights {
 		if w.IsNegative() {
 			return fmt.Errorf("weights contain a negative amount: %s", w)
 		}
+		totalWeight = totalWeight.Add(w)
+	}
+	if !totalWeight.IsPositive() {
+		return fmt.Errorf("total weight must be positive")
 	}
 	return nil
 }
--- a/x/auction/types/auctions_test.go
+++ b/x/auction/types/auctions_test.go
@ -1,6 +1,7 @@
 package types

 import (
+	"fmt"
 	"testing"
 	"time"

@ -24,48 +25,65 @@ const (
 	TestAccAddress2         = "kava1pdfav2cjhry9k79nu6r8kgknnjtq6a7rcr0qlr"
 )

+func d(amount string) sdk.Dec               { return sdk.MustNewDecFromStr(amount) }
+func c(denom string, amount int64) sdk.Coin { return sdk.NewInt64Coin(denom, amount) }
+func i(n int64) sdk.Int                     { return sdk.NewInt(n) }
+func is(ns ...int64) (is []sdk.Int) {
+	for _, n := range ns {
+		is = append(is, sdk.NewInt(n))
+	}
+	return
+}
+
 func TestNewWeightedAddresses(t *testing.T) {

 	tests := []struct {
-		name       string
-		addresses  []sdk.AccAddress
-		weights    []sdk.Int
-		expectpass bool
+		name        string
+		addresses   []sdk.AccAddress
+		weights     []sdk.Int
+		expectedErr error
 	}{
 		{
-			"normal",
-			[]sdk.AccAddress{
+			name: "normal",
+			addresses: []sdk.AccAddress{
 				sdk.AccAddress([]byte(TestAccAddress1)),
 				sdk.AccAddress([]byte(TestAccAddress2)),
 			},
-			[]sdk.Int{
-				sdk.NewInt(6),
-				sdk.NewInt(8),
-			},
-			true,
+			weights:     is(6, 8),
+			expectedErr: nil,
 		},
 		{
-			"mismatched",
-			[]sdk.AccAddress{
+			name: "mismatched",
+			addresses: []sdk.AccAddress{
 				sdk.AccAddress([]byte(TestAccAddress1)),
 				sdk.AccAddress([]byte(TestAccAddress2)),
 			},
-			[]sdk.Int{
-				sdk.NewInt(6),
-			},
-			false,
+			weights:     is(6),
+			expectedErr: fmt.Errorf("number of addresses doesn't match number of weights, %d ≠ %d", 2, 1),
 		},
 		{
-			"negativeWeight",
-			[]sdk.AccAddress{
+			name: "negativeWeight",
+			addresses: []sdk.AccAddress{
 				sdk.AccAddress([]byte(TestAccAddress1)),
 				sdk.AccAddress([]byte(TestAccAddress2)),
 			},
-			[]sdk.Int{
-				sdk.NewInt(6),
-				sdk.NewInt(-8),
+			weights:     is(6, -8),
+			expectedErr: fmt.Errorf("weights contain a negative amount: %s", i(-8)),
+		},
+		{
+			name: "zero total weights",
+			addresses: []sdk.AccAddress{
+				sdk.AccAddress([]byte(TestAccAddress1)),
+				sdk.AccAddress([]byte(TestAccAddress2)),
 			},
-			false,
+			weights:     is(0, 0),
+			expectedErr: fmt.Errorf("total weight must be positive"),
+		},
+		{
+			name:        "no weights",
+			addresses:   nil,
+			weights:     nil,
+			expectedErr: fmt.Errorf("must be at least 1 weighted address"),
 		},
 	}

@ -75,27 +93,16 @@ func TestNewWeightedAddresses(t *testing.T) {
 			// Attempt to instantiate new WeightedAddresses
 			weightedAddresses, err := NewWeightedAddresses(tc.addresses, tc.weights)

-			if tc.expectpass {
-				// Confirm there is no error
-				require.Nil(t, err)
-
+			if tc.expectedErr != nil {
+				// Confirm the error
+				require.EqualError(t, err, tc.expectedErr.Error())
+			} else {
+				require.NoError(t, err)
 				// Check addresses, weights
 				require.Equal(t, tc.addresses, weightedAddresses.Addresses)
 				require.Equal(t, tc.weights, weightedAddresses.Weights)
-			} else {
-				// Confirm that there is an error
-				require.NotNil(t, err)
-
-				switch tc.name {
-				case "mismatched":
-					require.Contains(t, err.Error(), "number of addresses doesn't match number of weights")
-				case "negativeWeight":
-					require.Contains(t, err.Error(), "weights contain a negative amount")
-				default:
-					// Unexpected error state
-					t.Fail()
-				}
 			}
+
 		})
 	}
 }
--- a/x/auction/types/errors.go
+++ b/x/auction/types/errors.go
@ -7,30 +7,24 @@ import sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 var (
 	// ErrInvalidInitialAuctionID error for when the initial auction ID hasn't been set
 	ErrInvalidInitialAuctionID = sdkerrors.Register(ModuleName, 2, "initial auction ID hasn't been set")
-	// ErrInvalidModulePermissions error for when module doesn't have valid permissions
-	ErrInvalidModulePermissions = sdkerrors.Register(ModuleName, 3, "module does not have required permission")
 	// ErrUnrecognizedAuctionType error for unrecognized auction type
-	ErrUnrecognizedAuctionType = sdkerrors.Register(ModuleName, 4, "unrecognized auction type")
+	ErrUnrecognizedAuctionType = sdkerrors.Register(ModuleName, 3, "unrecognized auction type")
 	// ErrAuctionNotFound error for when an auction is not found
-	ErrAuctionNotFound = sdkerrors.Register(ModuleName, 5, "auction not found")
+	ErrAuctionNotFound = sdkerrors.Register(ModuleName, 4, "auction not found")
 	// ErrAuctionHasNotExpired error for attempting to close an auction that has not passed its end time
-	ErrAuctionHasNotExpired = sdkerrors.Register(ModuleName, 6, "auction can't be closed as curent block time has not passed auction end time")
+	ErrAuctionHasNotExpired = sdkerrors.Register(ModuleName, 5, "auction can't be closed as curent block time has not passed auction end time")
 	// ErrAuctionHasExpired error for when an auction is closed and unavailable for bidding
-	ErrAuctionHasExpired = sdkerrors.Register(ModuleName, 7, "auction has closed")
+	ErrAuctionHasExpired = sdkerrors.Register(ModuleName, 6, "auction has closed")
 	// ErrInvalidBidDenom error for when bid denom doesn't match auction bid denom
-	ErrInvalidBidDenom = sdkerrors.Register(ModuleName, 8, "bid denom doesn't match auction bid denom")
+	ErrInvalidBidDenom = sdkerrors.Register(ModuleName, 7, "bid denom doesn't match auction bid denom")
 	// ErrInvalidLotDenom error for when lot denom doesn't match auction lot denom
-	ErrInvalidLotDenom = sdkerrors.Register(ModuleName, 9, "lot denom doesn't match auction lot denom")
+	ErrInvalidLotDenom = sdkerrors.Register(ModuleName, 8, "lot denom doesn't match auction lot denom")
 	// ErrBidTooSmall error for when bid is not greater than auction's min bid amount
-	ErrBidTooSmall = sdkerrors.Register(ModuleName, 10, "bid is not greater than auction's min new bid amount")
+	ErrBidTooSmall = sdkerrors.Register(ModuleName, 9, "bid is not greater than auction's min new bid amount")
 	// ErrBidTooLarge error for when bid is larger than auction's maximum allowed bid
-	ErrBidTooLarge = sdkerrors.Register(ModuleName, 11, "bid is greater than auction's max bid")
+	ErrBidTooLarge = sdkerrors.Register(ModuleName, 10, "bid is greater than auction's max bid")
 	// ErrLotTooSmall error for when lot is less than zero
-	ErrLotTooSmall = sdkerrors.Register(ModuleName, 12, "lot is not greater than auction's min new lot amount")
+	ErrLotTooSmall = sdkerrors.Register(ModuleName, 11, "lot is not greater than auction's min new lot amount")
 	// ErrLotTooLarge error for when lot is not smaller than auction's max new lot amount
-	ErrLotTooLarge = sdkerrors.Register(ModuleName, 13, "lot is greater than auction's max new lot amount")
-	// ErrCollateralAuctionIsInReversePhase error for when attempting to place a forward bid on a collateral auction in reverse phase
-	ErrCollateralAuctionIsInReversePhase = sdkerrors.Register(ModuleName, 14, "invalid bid: auction is in reverse phase")
-	// ErrCollateralAuctionIsInForwardPhase error for when attempting to place a reverse bid on a collateral auction in forward phase
-	ErrCollateralAuctionIsInForwardPhase = sdkerrors.Register(ModuleName, 15, "invalid bid: auction is in forward phase")
+	ErrLotTooLarge = sdkerrors.Register(ModuleName, 12, "lot is greater than auction's max new lot amount")
 )
--- a/x/auction/types/events.go
+++ b/x/auction/types/events.go
@ -1,6 +1,6 @@
 package types

-// Events for auction module
+// Events for the module
 const (
 	EventTypeAuctionStart = "auction_start"
 	EventTypeAuctionBid   = "auction_bid"
@ -10,9 +10,9 @@ const (
 	AttributeKeyAuctionID   = "auction_id"
 	AttributeKeyAuctionType = "auction_type"
 	AttributeKeyBidder      = "bidder"
-	AttributeKeyBidDenom    = "bid_denom"
-	AttributeKeyLotDenom    = "lot_denom"
-	AttributeKeyBidAmount   = "bid_amount"
-	AttributeKeyLotAmount   = "lot_amount"
+	AttributeKeyLot         = "lot"
+	AttributeKeyMaxBid      = "max_bid"
+	AttributeKeyBid         = "bid"
 	AttributeKeyEndTime     = "end_time"
+	AttributeKeyCloseBlock  = "close_block"
 )
--- a/x/auction/types/genesis.go
+++ b/x/auction/types/genesis.go
@ -76,7 +76,7 @@ func (gs GenesisState) Validate() error {
 		ids[a.GetID()] = true

 		if a.GetID() >= gs.NextAuctionID {
-			return fmt.Errorf("found auction ID >= the nextAuctionID (%d >= %d)", a.GetID(), gs.NextAuctionID)
+			return fmt.Errorf("found auction ID ≥ the nextAuctionID (%d ≥ %d)", a.GetID(), gs.NextAuctionID)
 		}
 	}
 	return nil
--- a/x/auction/types/msg_test.go
+++ b/x/auction/types/msg_test.go
@ -39,5 +39,3 @@ func TestMsgPlaceBid_ValidateBasic(t *testing.T) {
 		})
 	}
 }
-
-func c(denom string, amount int64) sdk.Coin { return sdk.NewInt64Coin(denom, amount) }
--- a/x/auction/types/params_test.go
+++ b/x/auction/types/params_test.go
@ -5,8 +5,6 @@ import (
 	"time"

 	"github.com/stretchr/testify/require"
-
-	sdk "github.com/cosmos/cosmos-sdk/types"
 )

 func TestParams_Validate(t *testing.T) {
@ -105,5 +103,3 @@ func TestParams_Validate(t *testing.T) {
 		})
 	}
 }
-
-func d(amount string) sdk.Dec { return sdk.MustNewDecFromStr(amount) }
--- a/x/cdp/keeper/auctions.go
+++ b/x/cdp/keeper/auctions.go
@ -11,98 +11,15 @@ const (
 	dump = 100
 )

-type partialDeposit struct {
-	Depositor sdk.AccAddress
-	Amount    sdk.Coin
-	DebtShare sdk.Int
-}
-
-func newPartialDeposit(depositor sdk.AccAddress, amount sdk.Coin, ds sdk.Int) partialDeposit {
-	return partialDeposit{
-		Depositor: depositor,
-		Amount:    amount,
-		DebtShare: ds,
-	}
-}
-
-type partialDeposits []partialDeposit
-
-func (pd partialDeposits) SumCollateral() (sum sdk.Int) {
-	sum = sdk.ZeroInt()
-	for _, d := range pd {
-		sum = sum.Add(d.Amount.Amount)
-	}
-	return
-}
-
-func (pd partialDeposits) SumDebt() (sum sdk.Int) {
-	sum = sdk.ZeroInt()
-	for _, d := range pd {
-		sum = sum.Add(d.DebtShare)
-	}
-	return
-}
-
 // AuctionCollateral creates auctions from the input deposits which attempt to raise the corresponding amount of debt
 func (k Keeper) AuctionCollateral(ctx sdk.Context, deposits types.Deposits, debt sdk.Int, bidDenom string) error {
-	auctionSize := k.getAuctionSize(ctx, deposits[0].Amount.Denom)
-	partialAuctionDeposits := partialDeposits{}
-	totalCollateral := deposits.SumCollateral()
-	for totalCollateral.GT(sdk.ZeroInt()) {
-		for i, dep := range deposits {
-			if dep.Amount.IsZero() {
-				continue
-			}
-			collateralAmount := dep.Amount.Amount
-			collateralDenom := dep.Amount.Denom
-			// create auctions from individual deposits that are larger than the auction size
-			debtChange, collateralChange, err := k.CreateAuctionsFromDeposit(ctx, dep, debt, totalCollateral, auctionSize, bidDenom)
-			if err != nil {
-				return err
-			}
-			debt = debt.Sub(debtChange)
-			totalCollateral = totalCollateral.Sub(collateralChange)
-			dep.Amount = sdk.NewCoin(collateralDenom, collateralAmount.Sub(collateralChange))
-			collateralAmount = collateralAmount.Sub(collateralChange)
-			// if there is leftover collateral that is less than a lot
-			if !dep.Amount.IsZero() {
-				// figure out how much debt this deposit accounts for
-				// (depositCollateral / totalCollateral) * totalDebtFromCDP
-				debtCoveredByDeposit := (collateralAmount.Quo(totalCollateral)).Mul(debt)
-				// if adding this deposit to the other partial deposits is less than a lot
-				if (partialAuctionDeposits.SumCollateral().Add(collateralAmount)).LT(auctionSize) {
-					// append the deposit to the partial deposits and zero out the deposit
-					pd := newPartialDeposit(dep.Depositor, dep.Amount, debtCoveredByDeposit)
-					partialAuctionDeposits = append(partialAuctionDeposits, pd)
-					dep.Amount = sdk.NewCoin(collateralDenom, sdk.ZeroInt())
-				} else {
-					// if the sum of partial deposits now makes a lot
-					partialCollateral := sdk.NewCoin(collateralDenom, auctionSize.Sub(partialAuctionDeposits.SumCollateral()))
-					partialAmount := partialCollateral.Amount
-					partialDebt := (partialAmount.Quo(collateralAmount)).Mul(debtCoveredByDeposit)

-					// create a partial deposit from the deposit
-					partialDep := newPartialDeposit(dep.Depositor, partialCollateral, partialDebt)
-					// append it to the partial deposits
-					partialAuctionDeposits = append(partialAuctionDeposits, partialDep)
-					// create an auction from the partial deposits
-					debtChange, collateralChange, err := k.CreateAuctionFromPartialDeposits(ctx, partialAuctionDeposits, debt, totalCollateral, auctionSize, bidDenom)
-					if err != nil {
-						return err
-					}
-					debt = debt.Sub(debtChange)
-					totalCollateral = totalCollateral.Sub(collateralChange)
-					// reset partial deposits and update the deposit amount
-					partialAuctionDeposits = partialDeposits{}
-					dep.Amount = sdk.NewCoin(collateralDenom, collateralAmount.Sub(partialAmount))
-				}
-			}
-			deposits[i] = dep
-			totalCollateral = deposits.SumCollateral()
-		}
-	}
-	if partialAuctionDeposits.SumCollateral().GT(sdk.ZeroInt()) {
-		_, _, err := k.CreateAuctionFromPartialDeposits(ctx, partialAuctionDeposits, debt, totalCollateral, partialAuctionDeposits.SumCollateral(), bidDenom)
+	auctionSize := k.getAuctionSize(ctx, deposits[0].Amount.Denom)
+	totalCollateral := deposits.SumCollateral()
+	for _, deposit := range deposits {
+
+		debtCoveredByDeposit := (sdk.NewDecFromInt(deposit.Amount.Amount).Quo(sdk.NewDecFromInt(totalCollateral))).Mul(sdk.NewDecFromInt(debt)).RoundInt()
+		err := k.CreateAuctionsFromDeposit(ctx, deposit.Amount, deposit.Depositor, debtCoveredByDeposit, auctionSize, bidDenom)
 		if err != nil {
 			return err
 		}
@ -110,54 +27,38 @@ func (k Keeper) AuctionCollateral(ctx sdk.Context, deposits types.Deposits, debt
 	return nil
 }

-// CreateAuctionsFromDeposit creates auctions from the input deposit until there is less than auctionSize left on the deposit
+// CreateAuctionsFromDeposit creates auctions from the input deposit
 func (k Keeper) CreateAuctionsFromDeposit(
-	ctx sdk.Context, dep types.Deposit, debt sdk.Int, totalCollateral sdk.Int, auctionSize sdk.Int,
-	principalDenom string) (debtChange sdk.Int, collateralChange sdk.Int, err error) {
-	debtChange = sdk.ZeroInt()
-	collateralChange = sdk.ZeroInt()
-	depositAmount := dep.Amount.Amount
-	depositDenom := dep.Amount.Denom
-	for depositAmount.GTE(auctionSize) {
-		// figure out how much debt is covered by one lots worth of collateral
-		depositDebtAmount := (sdk.NewDecFromInt(auctionSize).Quo(sdk.NewDecFromInt(totalCollateral))).Mul(sdk.NewDecFromInt(debt)).RoundInt()
-		penalty := k.ApplyLiquidationPenalty(ctx, depositDenom, depositDebtAmount)
-		// start an auction for one lot, attempting to raise depositDebtAmount plus the liquidation penalty
+	ctx sdk.Context, collateral sdk.Coin, returnAddr sdk.AccAddress, debt, auctionSize sdk.Int,
+	principalDenom string) (err error) {
+
+	amountToAuction := collateral.Amount
+	totalCollateralAmount := collateral.Amount
+	remainingDebt := debt
+	if !amountToAuction.IsPositive() {
+		return nil
+	}
+	for amountToAuction.GT(auctionSize) {
+		debtCoveredByAuction := (sdk.NewDecFromInt(auctionSize).Quo(sdk.NewDecFromInt(totalCollateralAmount))).Mul(sdk.NewDecFromInt(debt)).RoundInt()
+		penalty := k.ApplyLiquidationPenalty(ctx, collateral.Denom, debtCoveredByAuction)
 		_, err := k.auctionKeeper.StartCollateralAuction(
-			ctx, types.LiquidatorMacc, sdk.NewCoin(depositDenom, auctionSize), sdk.NewCoin(principalDenom, depositDebtAmount.Add(penalty)), []sdk.AccAddress{dep.Depositor},
-			[]sdk.Int{auctionSize}, sdk.NewCoin(k.GetDebtDenom(ctx), depositDebtAmount))
+			ctx, types.LiquidatorMacc, sdk.NewCoin(collateral.Denom, auctionSize), sdk.NewCoin(principalDenom, debtCoveredByAuction.Add(penalty)), []sdk.AccAddress{returnAddr},
+			[]sdk.Int{auctionSize}, sdk.NewCoin(k.GetDebtDenom(ctx), debtCoveredByAuction))
 		if err != nil {
-			return sdk.ZeroInt(), sdk.ZeroInt(), err
+			return err
 		}
-		depositAmount = depositAmount.Sub(auctionSize)
-		totalCollateral = totalCollateral.Sub(auctionSize)
-		debt = debt.Sub(depositDebtAmount)
-		// subtract one lot's worth of debt from the total debt covered by this deposit
-		debtChange = debtChange.Add(depositDebtAmount)
-		collateralChange = collateralChange.Add(auctionSize)
-
+		amountToAuction = amountToAuction.Sub(auctionSize)
+		remainingDebt = remainingDebt.Sub(debtCoveredByAuction)
 	}
-	return debtChange, collateralChange, nil
-}
-
-// CreateAuctionFromPartialDeposits creates an auction from the input partial deposits
-func (k Keeper) CreateAuctionFromPartialDeposits(ctx sdk.Context, partialDeps partialDeposits, debt sdk.Int, collateral sdk.Int, auctionSize sdk.Int, bidDenom string) (debtChange, collateralChange sdk.Int, err error) {
-
-	returnAddrs := []sdk.AccAddress{}
-	returnWeights := []sdk.Int{}
-	depositDenom := partialDeps[0].Amount.Denom
-	for _, pd := range partialDeps {
-		returnAddrs = append(returnAddrs, pd.Depositor)
-		returnWeights = append(returnWeights, pd.DebtShare)
-	}
-	penalty := k.ApplyLiquidationPenalty(ctx, depositDenom, partialDeps.SumDebt())
-	_, err = k.auctionKeeper.StartCollateralAuction(ctx, types.LiquidatorMacc, sdk.NewCoin(partialDeps[0].Amount.Denom, auctionSize), sdk.NewCoin(bidDenom, partialDeps.SumDebt().Add(penalty)), returnAddrs, returnWeights, sdk.NewCoin(k.GetDebtDenom(ctx), partialDeps.SumDebt()))
+	penalty := k.ApplyLiquidationPenalty(ctx, collateral.Denom, remainingDebt)
+	_, err = k.auctionKeeper.StartCollateralAuction(
+		ctx, types.LiquidatorMacc, sdk.NewCoin(collateral.Denom, amountToAuction), sdk.NewCoin(principalDenom, remainingDebt.Add(penalty)), []sdk.AccAddress{returnAddr},
+		[]sdk.Int{amountToAuction}, sdk.NewCoin(k.GetDebtDenom(ctx), remainingDebt))
 	if err != nil {
-		return sdk.ZeroInt(), sdk.ZeroInt(), err
+		return err
 	}
-	debtChange = partialDeps.SumDebt()
-	collateralChange = partialDeps.SumCollateral()
-	return debtChange, collateralChange, nil
+
+	return nil
 }

 // NetSurplusAndDebt burns surplus and debt coins equal to the minimum of surplus and debt balances held by the liquidator module account
--- a/x/cdp/keeper/seize.go
+++ b/x/cdp/keeper/seize.go
@ -13,8 +13,8 @@ import (
 // 1. updates the fees for the input cdp,
 // 2. sends collateral for all deposits from the cdp module to the liquidator module account
 // 3. Applies the liquidation penalty and mints the corresponding amount of debt coins in the cdp module
-// 3. moves debt coins from the cdp module to the liquidator module account,
-// 4. decrements the total amount of principal outstanding for that collateral type
+// 4. moves debt coins from the cdp module to the liquidator module account,
+// 5. decrements the total amount of principal outstanding for that collateral type
 // (this is the equivalent of saying that fees are no longer accumulated by a cdp once it gets liquidated)
 func (k Keeper) SeizeCollateral(ctx sdk.Context, cdp types.CDP) error {
 	// Calculate the previous collateral ratio