diff --git a/x/precisebank/keeper/invariants.go b/x/precisebank/keeper/invariants.go
index 70318ff9..66b62b73 100644
--- a/x/precisebank/keeper/invariants.go
+++ b/x/precisebank/keeper/invariants.go
@@ -14,6 +14,7 @@ func RegisterInvariants(
 	k Keeper,
 	bk types.BankKeeper,
 ) {
+	ir.RegisterRoute(types.ModuleName, "reserve-backs-fractions", ReserveBacksFractionsInvariant(k))
 	ir.RegisterRoute(types.ModuleName, "balance-remainder-total", BalancedFractionalTotalInvariant(k))
 	ir.RegisterRoute(types.ModuleName, "valid-fractional-balances", ValidFractionalAmountsInvariant(k))
 	ir.RegisterRoute(types.ModuleName, "valid-remainder-amount", ValidRemainderAmountInvariant(k))
@@ -23,7 +24,12 @@ func RegisterInvariants(
 // AllInvariants runs all invariants of the X/precisebank module.
 func AllInvariants(k Keeper) sdk.Invariant {
 	return func(ctx sdk.Context) (string, bool) {
-		res, stop := BalancedFractionalTotalInvariant(k)(ctx)
+		res, stop := ReserveBacksFractionsInvariant(k)(ctx)
+		if stop {
+			return res, stop
+		}
+
+		res, stop = BalancedFractionalTotalInvariant(k)(ctx)
 		if stop {
 			return res, stop
 		}
@@ -47,6 +53,47 @@ func AllInvariants(k Keeper) sdk.Invariant {
 	}
 }
 
+// ReserveBacksFractionsInvariant checks that the total amount of backing
+// coins in the reserve is equal to the total amount of fractional balances,
+// such that the backing is always available to redeem all fractional balances
+// and there are no extra coins in the reserve that are not backing any
+// fractional balances.
+func ReserveBacksFractionsInvariant(k Keeper) sdk.Invariant {
+	return func(ctx sdk.Context) (string, bool) {
+		var (
+			msg    string
+			broken bool
+		)
+
+		fractionalBalSum := k.GetTotalSumFractionalBalances(ctx)
+		remainderAmount := k.GetRemainderAmount(ctx)
+
+		// Get the total amount of backing coins in the reserve
+		moduleAddr := k.ak.GetModuleAddress(types.ModuleName)
+		reserveIntegerBalance := k.bk.GetBalance(ctx, moduleAddr, types.IntegerCoinDenom)
+		reserveExtendedBalance := reserveIntegerBalance.Amount.Mul(types.ConversionFactor())
+
+		// The total amount of backing coins in the reserve should be equal to
+		// fractional balances + remainder amount
+		totalRequiredBacking := fractionalBalSum.Add(remainderAmount)
+
+		broken = !reserveExtendedBalance.Equal(totalRequiredBacking)
+		msg = fmt.Sprintf(
+			"%s reserve balance %s mismatches %s (fractional balances %s + remainder %s)\n",
+			types.ExtendedCoinDenom,
+			reserveExtendedBalance,
+			totalRequiredBacking,
+			fractionalBalSum,
+			remainderAmount,
+		)
+
+		return sdk.FormatInvariant(
+			types.ModuleName, "module reserve backing total fractional balances",
+			msg,
+		), broken
+	}
+}
+
 // ValidFractionalAmountsInvariant checks that all individual fractional
 // balances are valid.
 func ValidFractionalAmountsInvariant(k Keeper) sdk.Invariant {
diff --git a/x/precisebank/keeper/invariants_integration_test.go b/x/precisebank/keeper/invariants_integration_test.go
new file mode 100644
index 00000000..99740355
--- /dev/null
+++ b/x/precisebank/keeper/invariants_integration_test.go
@@ -0,0 +1,129 @@
+package keeper_test
+
+import (
+	"testing"
+
+	sdkmath "cosmossdk.io/math"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/kava-labs/kava/x/precisebank/keeper"
+	"github.com/kava-labs/kava/x/precisebank/testutil"
+	"github.com/kava-labs/kava/x/precisebank/types"
+	"github.com/stretchr/testify/suite"
+)
+
+type invariantsIntegrationTestSuite struct {
+	testutil.Suite
+}
+
+func (suite *invariantsIntegrationTestSuite) SetupTest() {
+	suite.Suite.SetupTest()
+}
+
+func TestInvariantsIntegrationTest(t *testing.T) {
+	suite.Run(t, new(invariantsIntegrationTestSuite))
+}
+
+func (suite *invariantsIntegrationTestSuite) FundReserve(amt sdkmath.Int) {
+	coins := sdk.NewCoins(sdk.NewCoin(types.IntegerCoinDenom, amt))
+	err := suite.BankKeeper.MintCoins(suite.Ctx, types.ModuleName, coins)
+	suite.Require().NoError(err)
+}
+
+func (suite *invariantsIntegrationTestSuite) TestReserveBackingFractionalInvariant() {
+	tests := []struct {
+		name       string
+		setupFn    func(ctx sdk.Context, k keeper.Keeper)
+		wantBroken bool
+		wantMsg    string
+	}{
+		{
+			"valid - empty state",
+			func(_ sdk.Context, _ keeper.Keeper) {},
+			false,
+			"",
+		},
+		{
+			"valid - fractional balances, no remainder",
+			func(ctx sdk.Context, k keeper.Keeper) {
+				k.SetFractionalBalance(ctx, sdk.AccAddress{1}, types.ConversionFactor().QuoRaw(2))
+				k.SetFractionalBalance(ctx, sdk.AccAddress{2}, types.ConversionFactor().QuoRaw(2))
+				// 1 integer backs same amount fractional
+				suite.FundReserve(sdk.NewInt(1))
+			},
+			false,
+			"",
+		},
+		{
+			"valid - fractional balances, with remainder",
+			func(ctx sdk.Context, k keeper.Keeper) {
+				k.SetFractionalBalance(ctx, sdk.AccAddress{1}, types.ConversionFactor().QuoRaw(2))
+				k.SetRemainderAmount(ctx, types.ConversionFactor().QuoRaw(2))
+				// 1 integer backs same amount fractional including remainder
+				suite.FundReserve(sdk.NewInt(1))
+			},
+			false,
+			"",
+		},
+		{
+			"invalid - no fractional balances, non-zero remainder",
+			func(ctx sdk.Context, k keeper.Keeper) {
+				k.SetRemainderAmount(ctx, types.ConversionFactor().QuoRaw(2))
+			},
+			true,
+			"precisebank: module reserve backing total fractional balances invariant\nakava reserve balance 0 mismatches 500000000000 (fractional balances 0 + remainder 500000000000)\n\n",
+		},
+		{
+			"invalid - insufficient reserve backing",
+			func(ctx sdk.Context, k keeper.Keeper) {
+				amt := types.ConversionFactor().QuoRaw(2)
+
+				// 0.5 int coins x 4
+				k.SetFractionalBalance(ctx, sdk.AccAddress{1}, amt)
+				k.SetFractionalBalance(ctx, sdk.AccAddress{2}, amt)
+				k.SetFractionalBalance(ctx, sdk.AccAddress{3}, amt)
+				k.SetRemainderAmount(ctx, amt)
+
+				// Needs 2 to back 0.5 x 4
+				suite.FundReserve(sdk.NewInt(1))
+			},
+			true,
+			"precisebank: module reserve backing total fractional balances invariant\nakava reserve balance 1000000000000 mismatches 2000000000000 (fractional balances 1500000000000 + remainder 500000000000)\n\n",
+		},
+		{
+			"invalid - excess reserve backing",
+			func(ctx sdk.Context, k keeper.Keeper) {
+				amt := types.ConversionFactor().QuoRaw(2)
+
+				// 0.5 int coins x 4
+				k.SetFractionalBalance(ctx, sdk.AccAddress{1}, amt)
+				k.SetFractionalBalance(ctx, sdk.AccAddress{2}, amt)
+				k.SetFractionalBalance(ctx, sdk.AccAddress{3}, amt)
+				k.SetRemainderAmount(ctx, amt)
+
+				// Needs 2 to back 0.5 x 4
+				suite.FundReserve(sdk.NewInt(3))
+			},
+			true,
+			"precisebank: module reserve backing total fractional balances invariant\nakava reserve balance 3000000000000 mismatches 2000000000000 (fractional balances 1500000000000 + remainder 500000000000)\n\n",
+		},
+	}
+
+	for _, tt := range tests {
+		suite.Run(tt.name, func() {
+			// Reset each time
+			suite.SetupTest()
+
+			tt.setupFn(suite.Ctx, suite.Keeper)
+
+			invariantFn := keeper.ReserveBacksFractionsInvariant(suite.Keeper)
+			msg, broken := invariantFn(suite.Ctx)
+
+			if tt.wantBroken {
+				suite.Require().True(broken, "invariant should be broken but is not")
+				suite.Require().Equal(tt.wantMsg, msg)
+			} else {
+				suite.Require().Falsef(broken, "invariant should not be broken but is: %s", msg)
+			}
+		})
+	}
+}
diff --git a/x/precisebank/keeper/mint.go b/x/precisebank/keeper/mint.go
index 1e0fabc3..98633a0f 100644
--- a/x/precisebank/keeper/mint.go
+++ b/x/precisebank/keeper/mint.go
@@ -63,13 +63,28 @@ func (k Keeper) MintCoins(ctx sdk.Context, moduleName string, amt sdk.Coins) err
 	return k.mintExtendedCoin(ctx, moduleName, extendedAmount)
 }
 
-// mintExtendedCoin manages the minting of extended coins, and no other coins.
+// mintExtendedCoin manages the minting of only extended coins. This also
+// handles integer carry over from fractional balance to integer balance if
+// necessary depending on the fractional balance and minting amount. Ensures
+// that the reserve fully backs the additional minted amount, minting any extra
+// reserve integer coins if necessary.
+// 4 Cases:
+// 1. NO integer carry over, >= 0 remainder - no reserve mint
+// 2. NO integer carry over, negative remainder - mint 1 to reserve
+// 3. Integer carry over, >= 0 remainder
+//   - Transfer 1 integer from reserve -> account
+//
+// 4. Integer carry over, negative remainder
+//   - Transfer 1 integer from reserve -> account
+//   - Mint 1 to reserve
+//     Optimization:
+//   - Increase direct account mint amount by 1, no extra reserve mint
 func (k Keeper) mintExtendedCoin(
 	ctx sdk.Context,
-	moduleName string,
+	recipientModuleName string,
 	amt sdkmath.Int,
 ) error {
-	moduleAddr := k.ak.GetModuleAddress(moduleName)
+	moduleAddr := k.ak.GetModuleAddress(recipientModuleName)
 
 	// Get current module account fractional balance - 0 if not found
 	fractionalAmount := k.GetFractionalBalance(ctx, moduleAddr)
@@ -78,19 +93,57 @@ func (k Keeper) mintExtendedCoin(
 	integerMintAmount := amt.Quo(types.ConversionFactor())
 	fractionalMintAmount := amt.Mod(types.ConversionFactor())
 
+	// Get previous remainder amount, as we need to it before carry calculation
+	// for the optimization path.
+	prevRemainder := k.GetRemainderAmount(ctx)
+
+	// Deduct new remainder with minted fractional amount. This will result in
+	// two cases:
+	// 1. Zero or positive remainder: remainder is sufficient to back the minted
+	//   fractional amount. Reserve is also sufficient to back the minted amount
+	//   so no additional reserve integer coin is needed.
+	// 2. Negative remainder: remainder is insufficient to back the minted
+	//   fractional amount. Reserve will need to be increased to back the mint
+	//   amount.
+	newRemainder := prevRemainder.Sub(fractionalMintAmount)
+
 	// Get new fractional balance after minting, this could be greater than
 	// the conversion factor and must be checked for carry over to integer mint
 	// amount as being set as-is may cause fractional balance exceeding max.
 	newFractionalBalance := fractionalAmount.Add(fractionalMintAmount)
 
-	// If it carries over, add 1 to integer mint amount. In this case, it will
-	// always be 1:
+	// Case #3 - Integer carry, remainder is sufficient (0 or positive)
+	if newFractionalBalance.GTE(types.ConversionFactor()) && newRemainder.GTE(sdkmath.ZeroInt()) {
+		// Carry should send from reserve -> account, instead of minting an
+		// extra integer coin. Otherwise doing an extra mint will require a burn
+		// from reserves to maintain exact backing.
+		carryCoin := sdk.NewCoin(types.IntegerCoinDenom, sdkmath.OneInt())
+
+		// SendCoinsFromModuleToModule allows for sending coins even if the
+		// recipient module account is blocked.
+		if err := k.bk.SendCoinsFromModuleToModule(
+			ctx,
+			types.ModuleName,
+			recipientModuleName,
+			sdk.NewCoins(carryCoin),
+		); err != nil {
+			return err
+		}
+	}
+
+	// Case #4 - Integer carry, remainder is insufficient
+	// This is the optimization path where the integer mint amount is increased
+	// by 1, instead of doing both a reserve -> account transfer and reserve mint.
+	if newFractionalBalance.GTE(types.ConversionFactor()) && newRemainder.IsNegative() {
+		integerMintAmount = integerMintAmount.AddRaw(1)
+	}
+
+	// If it carries over, adjust the fractional balance to account for the
+	// previously added 1 integer amount.
 	// fractional amounts x and y where both x and y < ConversionFactor
 	// x + y < (2 * ConversionFactor) - 2
 	// x + y < 1 integer amount + fractional amount
 	if newFractionalBalance.GTE(types.ConversionFactor()) {
-		// Carry over to integer mint amount
-		integerMintAmount = integerMintAmount.AddRaw(1)
 		// Subtract 1 integer equivalent amount of fractional balance. Same
 		// behavior as using .Mod() in this case.
 		newFractionalBalance = newFractionalBalance.Sub(types.ConversionFactor())
@@ -103,7 +156,7 @@ func (k Keeper) mintExtendedCoin(
 
 		if err := k.bk.MintCoins(
 			ctx,
-			moduleName,
+			recipientModuleName,
 			sdk.NewCoins(integerMintCoin),
 		); err != nil {
 			return err
@@ -115,20 +168,28 @@ func (k Keeper) mintExtendedCoin(
 
 	// ----------------------------------------
 	// Update remainder & reserves to back minted fractional coins
-	prevRemainder := k.GetRemainderAmount(ctx)
-	// Deduct new remainder with minted fractional amount
-	newRemainder := prevRemainder.Sub(fractionalMintAmount)
 
-	if prevRemainder.LT(fractionalMintAmount) {
-		// Need additional 1 integer coin in reserve to back minted fractional
+	// Mint an additional reserve integer coin if remainder is insufficient.
+	// The remainder is the amount of fractional coins that can be minted and
+	// still be fully backed by reserve. If the remainder is less than the
+	// minted fractional amount, then the reserve needs to be increased to
+	// back the additional fractional amount.
+	// Optimization: This is only done when the integer amount does NOT carry,
+	// as a direct account mint is done instead of integer carry transfer +
+	// insufficient remainder reserve mint.
+	wasCarried := fractionalAmount.Add(fractionalMintAmount).GTE(types.ConversionFactor())
+	if prevRemainder.LT(fractionalMintAmount) && !wasCarried {
+		// Always only 1 integer coin, as fractionalMintAmount < ConversionFactor
 		reserveMintCoins := sdk.NewCoins(sdk.NewCoin(types.IntegerCoinDenom, sdkmath.OneInt()))
 		if err := k.bk.MintCoins(ctx, types.ModuleName, reserveMintCoins); err != nil {
 			return fmt.Errorf("failed to mint %s for reserve: %w", reserveMintCoins, err)
 		}
+	}
 
-		// Update remainder with value of minted integer coin. newRemainder is
-		// currently negative at this point. This also means that it will always
-		// be < conversionFactor after this operation and not require a Mod().
+	// newRemainder will be negative if prevRemainder < fractionalMintAmount.
+	// This needs to be adjusted back to the corresponding positive value. The
+	// remainder will be always < conversionFactor after add if it is negative.
+	if newRemainder.IsNegative() {
 		newRemainder = newRemainder.Add(types.ConversionFactor())
 	}
 
diff --git a/x/precisebank/keeper/mint_integration_test.go b/x/precisebank/keeper/mint_integration_test.go
index 021b4100..4b99b01c 100644
--- a/x/precisebank/keeper/mint_integration_test.go
+++ b/x/precisebank/keeper/mint_integration_test.go
@@ -177,6 +177,39 @@ func (suite *mintIntegrationTestSuite) TestMintCoins() {
 				},
 			},
 		},
+		{
+			"fractional only with carry",
+			minttypes.ModuleName,
+			[]mintTest{
+				{
+					// Start with (1/4 * 3) = 0.75
+					mintAmount:  cs(ci(types.ExtendedCoinDenom, types.ConversionFactor().QuoRaw(4).MulRaw(3))),
+					wantBalance: cs(ci(types.ExtendedCoinDenom, types.ConversionFactor().QuoRaw(4).MulRaw(3))),
+				},
+				{
+					// Add another 0.50 to incur carry to test reserve on carry
+					mintAmount:  cs(ci(types.ExtendedCoinDenom, types.ConversionFactor().QuoRaw(2))),
+					wantBalance: cs(ci(types.ExtendedCoinDenom, types.ConversionFactor().QuoRaw(4).MulRaw(5))),
+				},
+			},
+		},
+		{
+			"fractional only, resulting in exact carry and 0 remainder",
+			minttypes.ModuleName,
+			[]mintTest{
+				// mint 0.5, acc = 0.5, reserve = 1
+				{
+					mintAmount:  cs(ci(types.ExtendedCoinDenom, types.ConversionFactor().QuoRaw(2))),
+					wantBalance: cs(ci(types.ExtendedCoinDenom, types.ConversionFactor().QuoRaw(2))),
+				},
+				// mint another 0.5, acc = 1, reserve = 0
+				// Reserve actually goes down by 1 for integer carry
+				{
+					mintAmount:  cs(ci(types.ExtendedCoinDenom, types.ConversionFactor().QuoRaw(2))),
+					wantBalance: cs(ci(types.ExtendedCoinDenom, types.ConversionFactor())),
+				},
+			},
+		},
 		{
 			"exact carry",
 			minttypes.ModuleName,
@@ -299,9 +332,8 @@ func (suite *mintIntegrationTestSuite) TestMintCoins() {
 
 				// Ensure reserve is backing all minted fractions
 				allInvariantsFn := keeper.AllInvariants(suite.Keeper)
-				res, stop := allInvariantsFn(suite.Ctx)
-				suite.Require().False(stop, "invariant should not be broken")
-				suite.Require().Empty(res, "unexpected invariant message: %s", res)
+				msg, stop := allInvariantsFn(suite.Ctx)
+				suite.Require().Falsef(stop, "invariant should not be broken: %s", msg)
 			}
 		})
 	}
@@ -311,6 +343,7 @@ func FuzzMintCoins(f *testing.F) {
 	f.Add(int64(0))
 	f.Add(int64(100))
 	f.Add(types.ConversionFactor().Int64())
+	f.Add(types.ConversionFactor().QuoRaw(2).Int64())
 	f.Add(types.ConversionFactor().MulRaw(5).Int64())
 	f.Add(types.ConversionFactor().MulRaw(2).AddRaw(123948723).Int64())
 
@@ -328,6 +361,8 @@ func FuzzMintCoins(f *testing.F) {
 
 		mintCount := int64(10)
 
+		suite.T().Logf("minting %d %d times", amount, mintCount)
+
 		// Mint 10 times to include mints from non-zero balances
 		for i := int64(0); i < mintCount; i++ {
 			err := suite.Keeper.MintCoins(
@@ -345,15 +380,15 @@ func FuzzMintCoins(f *testing.F) {
 		suite.Require().Equalf(
 			amount*mintCount,
 			bal.Amount.Int64(),
-			"unexpected balance after minting %d 5 times",
+			"unexpected balance after minting %d %d times",
 			amount,
+			mintCount,
 		)
 
 		// Run Invariants to ensure remainder is backing all minted fractions
 		// and in a valid state
-		allInvariantsFn := keeper.AllInvariants(suite.Keeper)
-		res, stop := allInvariantsFn(suite.Ctx)
-		suite.Require().False(stop, "invariant should not be broken")
-		suite.Require().Empty(res, "unexpected invariant message: %s", res)
+		res, stop := keeper.AllInvariants(suite.Keeper)(suite.Ctx)
+		suite.False(stop, "invariant should not be broken")
+		suite.Empty(res, "unexpected invariant message")
 	})
 }
diff --git a/x/precisebank/keeper/mint_test.go b/x/precisebank/keeper/mint_test.go
index 6be41fca..a7df18ec 100644
--- a/x/precisebank/keeper/mint_test.go
+++ b/x/precisebank/keeper/mint_test.go
@@ -289,6 +289,20 @@ func TestMintCoins_ExpectedCalls(t *testing.T) {
 					Once()
 			}
 
+			// ----------------------------------------
+			// Set expectations for reserve minting when fractional amounts
+			// are minted & remainder is insufficient
+			mintFractionalAmount := extCoins.Amount.Mod(types.ConversionFactor())
+			currentRemainder := td.keeper.GetRemainderAmount(td.ctx)
+
+			causesIntegerCarry := fBal.Add(mintFractionalAmount).GTE(types.ConversionFactor())
+			remainderEnough := currentRemainder.GTE(mintFractionalAmount)
+
+			// Optimization: Carry & insufficient remainder is directly minted
+			if causesIntegerCarry && !remainderEnough {
+				extCoins = extCoins.AddAmount(types.ConversionFactor())
+			}
+
 			// ----------------------------------------
 			// Set expectations for minting fractional coins
 			if !extCoins.IsNil() && extCoins.IsPositive() {
@@ -298,9 +312,9 @@ func TestMintCoins_ExpectedCalls(t *testing.T) {
 					Once()
 
 				// Initial integer balance is always 0 for this test
-				totalNewBalance := tt.startFractionalBalance.Add(extCoins.Amount)
-				mintIntegerAmount := totalNewBalance.Quo(types.ConversionFactor())
+				mintIntegerAmount := extCoins.Amount.Quo(types.ConversionFactor())
 
+				// Minted coins does NOT include roll-over, simply excludes
 				mintCoins := cs(ci(types.IntegerCoinDenom, mintIntegerAmount))
 
 				// Only expect MintCoins to be called with mint coins with
@@ -316,15 +330,20 @@ func TestMintCoins_ExpectedCalls(t *testing.T) {
 				}
 			}
 
-			// ----------------------------------------
-			// Set expectations for reserve minting when fractional amounts
-			// are minted & remainder is insufficient
-			mintFractionalAmount := extCoins.Amount.Mod(types.ConversionFactor())
-			currentRemainder := td.keeper.GetRemainderAmount(td.ctx)
+			if causesIntegerCarry && remainderEnough {
+				td.bk.EXPECT().
+					SendCoinsFromModuleToModule(
+						td.ctx,
+						types.ModuleName,
+						minttypes.ModuleName,
+						cs(c(types.IntegerCoinDenom, 1)),
+					).
+					Return(nil).
+					Once()
+			}
 
-			remainderEnough := currentRemainder.GTE(mintFractionalAmount)
-			if !remainderEnough {
-				reserveMintCoins := cs(ci(types.IntegerCoinDenom, sdkmath.OneInt()))
+			if !remainderEnough && !causesIntegerCarry {
+				reserveMintCoins := cs(c(types.IntegerCoinDenom, 1))
 				td.bk.EXPECT().
 					// Mints to x/precisebank
 					MintCoins(td.ctx, types.ModuleName, reserveMintCoins).