diff --git a/baseapp/baseapp_test.go b/baseapp/baseapp_test.go
index 5cc20185d4..de9a0253c5 100644
--- a/baseapp/baseapp_test.go
+++ b/baseapp/baseapp_test.go
@@ -328,7 +328,6 @@ func (tx testUpdatePowerTx) GetMsg() sdk.Msg                         { return tx
 func (tx testUpdatePowerTx) GetSignBytes() []byte                    { return nil }
 func (tx testUpdatePowerTx) ValidateBasic() sdk.Error                { return nil }
 func (tx testUpdatePowerTx) GetSigners() []sdk.Address               { return nil }
-func (tx testUpdatePowerTx) GetFeePayer() sdk.Address                { return nil }
 func (tx testUpdatePowerTx) GetSignatures() []sdk.StdSignature       { return nil }
 
 func TestValidatorChange(t *testing.T) {
diff --git a/client/builder/builder.go b/client/builder/builder.go
index e252f40af8..a64dfeda74 100644
--- a/client/builder/builder.go
+++ b/client/builder/builder.go
@@ -124,7 +124,7 @@ func SignAndBuild(msg sdk.Msg, cdc *wire.Codec) ([]byte, error) {
 	}}
 
 	// marshal bytes
-	tx := sdk.NewStdTx(signMsg.Msg, sigs)
+	tx := sdk.NewStdTx(signMsg.Msg, signMsg.Fee, sigs)
 
 	return cdc.MarshalBinary(tx)
 }
diff --git a/docs/guide.md b/docs/guide.md
index 1a6d21c82a..5c31d2e271 100644
--- a/docs/guide.md
+++ b/docs/guide.md
@@ -105,14 +105,6 @@ type Tx interface {
 
 	GetMsg() Msg
 
-	// The address that pays the base fee for this message.  The fee is
-	// deducted before the Msg is processed.
-	GetFeePayer() Address
-
-	// Get the canonical byte representation of the Tx.
-	// Includes any signatures (or empty slots).
-	GetTxBytes() []byte
-
 	// Signatures returns the signature of signers who signed the Msg.
 	// CONTRACT: Length returned is same as length of
 	// pubkeys returned from MsgKeySigners, and the order
@@ -148,8 +140,9 @@ case of Basecoin, the public key only needs to be included in the first
 transaction send by a given account - after that, the public key is forever
 stored by the application and can be left out of transactions.
 
-Transactions can also specify the address responsible for paying the
-transaction's fees using the `tx.GetFeePayer()` method.
+The address responsible for paying the transactions fee is the first address
+returned by msg.GetSigners(). The convenience function `FeePayer(tx Tx)` is provided
+to return this.
 
 The standard way to create a transaction from a message is to use the `StdTx`: 
 
diff --git a/docs/sdk/overview.rst b/docs/sdk/overview.rst
index bf7b23a606..9e79dd04ff 100644
--- a/docs/sdk/overview.rst
+++ b/docs/sdk/overview.rst
@@ -219,14 +219,6 @@ A transaction is a message with additional information for authentication:
     
     	GetMsg() Msg
     
-    	// The address that pays the base fee for this message.  The fee is
-    	// deducted before the Msg is processed.
-    	GetFeePayer() Address
-    
-    	// Get the canonical byte representation of the Tx.
-    	// Includes any signatures (or empty slots).
-    	GetTxBytes() []byte
-    
     	// Signatures returns the signature of signers who signed the Msg.
     	// CONTRACT: Length returned is same as length of
     	// pubkeys returned from MsgKeySigners, and the order
@@ -261,9 +253,6 @@ case of Basecoin, the public key only needs to be included in the first
 transaction send by a given account - after that, the public key is forever
 stored by the application and can be left out of transactions.
 
-Transactions can also specify the address responsible for paying the
-transaction's fees using the ``tx.GetFeePayer()`` method.
-
 The standard way to create a transaction from a message is to use the ``StdTx``: 
 
 ::
diff --git a/examples/basecoin/app/app_test.go b/examples/basecoin/app/app_test.go
index c2ef3e4547..66de2b68b4 100644
--- a/examples/basecoin/app/app_test.go
+++ b/examples/basecoin/app/app_test.go
@@ -29,6 +29,10 @@ var (
 	addr1 = priv1.PubKey().Address()
 	addr2 = crypto.GenPrivKeyEd25519().PubKey().Address()
 	coins = sdk.Coins{{"foocoin", 10}}
+	fee   = sdk.StdFee{
+		sdk.Coins{{"foocoin", 0}},
+		0,
+	}
 
 	sendMsg = bank.SendMsg{
 		Inputs:  []bank.Input{bank.NewInput(addr1, coins)},
@@ -82,8 +86,8 @@ func TestMsgs(t *testing.T) {
 
 	sequences := []int64{0}
 	for i, m := range msgs {
-		sig := priv1.Sign(sdk.StdSignBytes(chainID, sequences, m.msg))
-		tx := sdk.NewStdTx(m.msg, []sdk.StdSignature{{
+		sig := priv1.Sign(sdk.StdSignBytes(chainID, sequences, fee, m.msg))
+		tx := sdk.NewStdTx(m.msg, fee, []sdk.StdSignature{{
 			PubKey:    priv1.PubKey(),
 			Signature: sig,
 		}})
@@ -180,8 +184,8 @@ func TestSendMsgWithAccounts(t *testing.T) {
 
 	// Sign the tx
 	sequences := []int64{0}
-	sig := priv1.Sign(sdk.StdSignBytes(chainID, sequences, sendMsg))
-	tx := sdk.NewStdTx(sendMsg, []sdk.StdSignature{{
+	sig := priv1.Sign(sdk.StdSignBytes(chainID, sequences, fee, sendMsg))
+	tx := sdk.NewStdTx(sendMsg, fee, []sdk.StdSignature{{
 		PubKey:    priv1.PubKey(),
 		Signature: sig,
 	}})
@@ -213,7 +217,7 @@ func TestSendMsgWithAccounts(t *testing.T) {
 
 	// resigning the tx with the bumped sequence should work
 	sequences = []int64{1}
-	sig = priv1.Sign(sdk.StdSignBytes(chainID, sequences, tx.Msg))
+	sig = priv1.Sign(sdk.StdSignBytes(chainID, sequences, fee, tx.Msg))
 	tx.Signatures[0].Signature = sig
 	res = bapp.Deliver(tx)
 	assert.Equal(t, sdk.CodeOK, res.Code, res.Log)
@@ -270,9 +274,9 @@ func TestQuizMsg(t *testing.T) {
 func SignCheckDeliver(t *testing.T, bapp *BasecoinApp, msg sdk.Msg, seq int64, expPass bool) {
 
 	// Sign the tx
-	tx := sdk.NewStdTx(msg, []sdk.StdSignature{{
+	tx := sdk.NewStdTx(msg, fee, []sdk.StdSignature{{
 		PubKey:    priv1.PubKey(),
-		Signature: priv1.Sign(sdk.StdSignBytes(chainID, []int64{seq}, msg)),
+		Signature: priv1.Sign(sdk.StdSignBytes(chainID, []int64{seq}, fee, msg)),
 		Sequence:  seq,
 	}})
 
diff --git a/examples/basecoin/x/cool/types.go b/examples/basecoin/x/cool/types.go
index f721bfa19b..10515c8abe 100644
--- a/examples/basecoin/x/cool/types.go
+++ b/examples/basecoin/x/cool/types.go
@@ -37,7 +37,7 @@ func (msg SetTrendMsg) String() string {
 // Validate Basic is used to quickly disqualify obviously invalid messages quickly
 func (msg SetTrendMsg) ValidateBasic() sdk.Error {
 	if len(msg.Sender) == 0 {
-		return sdk.ErrUnrecognizedAddress(msg.Sender).Trace("")
+		return sdk.ErrUnrecognizedAddress(msg.Sender.String()).Trace("")
 	}
 	if strings.Contains(msg.Cool, "hot") {
 		return sdk.ErrUnauthorized("").Trace("hot is not cool")
@@ -88,7 +88,7 @@ func (msg QuizMsg) String() string {
 // Validate Basic is used to quickly disqualify obviously invalid messages quickly
 func (msg QuizMsg) ValidateBasic() sdk.Error {
 	if len(msg.Sender) == 0 {
-		return sdk.ErrUnrecognizedAddress(msg.Sender).Trace("")
+		return sdk.ErrUnrecognizedAddress(msg.Sender.String()).Trace("")
 	}
 	return nil
 }
diff --git a/examples/kvstore/tx.go b/examples/kvstore/tx.go
index fdecf63807..c9c30c885d 100644
--- a/examples/kvstore/tx.go
+++ b/examples/kvstore/tx.go
@@ -51,10 +51,6 @@ func (tx kvstoreTx) GetSignatures() []sdk.StdSignature {
 	return nil
 }
 
-func (tx kvstoreTx) GetFeePayer() sdk.Address {
-	return nil
-}
-
 // takes raw transaction bytes and decodes them into an sdk.Tx. An sdk.Tx has
 // all the signatures and can be used to authenticate.
 func decodeTx(txBytes []byte) (sdk.Tx, sdk.Error) {
diff --git a/mock/tx.go b/mock/tx.go
index efe60feb91..326946eaa5 100644
--- a/mock/tx.go
+++ b/mock/tx.go
@@ -64,10 +64,6 @@ func (tx kvstoreTx) GetSignatures() []sdk.StdSignature {
 	return nil
 }
 
-func (tx kvstoreTx) GetFeePayer() sdk.Address {
-	return nil
-}
-
 // takes raw transaction bytes and decodes them into an sdk.Tx. An sdk.Tx has
 // all the signatures and can be used to authenticate.
 func decodeTx(txBytes []byte) (sdk.Tx, sdk.Error) {
diff --git a/types/coin.go b/types/coin.go
index ad541b99bd..92871cd179 100644
--- a/types/coin.go
+++ b/types/coin.go
@@ -139,8 +139,14 @@ func (coins Coins) IsGTE(coinsB Coins) bool {
 }
 
 // IsZero returns true if there are no coins
+// or all coins are zero.
 func (coins Coins) IsZero() bool {
-	return len(coins) == 0
+	for _, coin := range coins {
+		if !coin.IsZero() {
+			return false
+		}
+	}
+	return true
 }
 
 // IsEqual returns true if the two sets of Coins have the same value
diff --git a/types/errors.go b/types/errors.go
index 9d8175e309..48e08b1164 100644
--- a/types/errors.go
+++ b/types/errors.go
@@ -27,6 +27,7 @@ const (
 	CodeInsufficientFunds   CodeType = 5
 	CodeUnknownRequest      CodeType = 6
 	CodeUnrecognizedAddress CodeType = 7
+	CodeInvalidPubKey       CodeType = 8
 
 	CodeGenesisParse CodeType = 0xdead // TODO: remove ?
 )
@@ -50,6 +51,8 @@ func CodeToDefaultMsg(code CodeType) string {
 		return "Unknown request"
 	case CodeUnrecognizedAddress:
 		return "Unrecognized address"
+	case CodeInvalidPubKey:
+		return "Invalid pubkey"
 	default:
 		return fmt.Sprintf("Unknown code %d", code)
 	}
@@ -81,8 +84,11 @@ func ErrInsufficientFunds(msg string) Error {
 func ErrUnknownRequest(msg string) Error {
 	return newError(CodeUnknownRequest, msg)
 }
-func ErrUnrecognizedAddress(addr Address) Error {
-	return newError(CodeUnrecognizedAddress, addr.String())
+func ErrUnrecognizedAddress(msg string) Error {
+	return newError(CodeUnrecognizedAddress, msg)
+}
+func ErrInvalidPubKey(msg string) Error {
+	return newError(CodeInvalidPubKey, msg)
 }
 
 //----------------------------------------
diff --git a/types/tx_msg.go b/types/tx_msg.go
index 141f9d050d..21bc330540 100644
--- a/types/tx_msg.go
+++ b/types/tx_msg.go
@@ -33,10 +33,6 @@ type Tx interface {
 	// Gets the Msg.
 	GetMsg() Msg
 
-	// The address that pays the base fee for this message.  The fee is
-	// deducted before the Msg is processed.
-	GetFeePayer() Address
-
 	// Signatures returns the signature of signers who signed the Msg.
 	// CONTRACT: Length returned is same as length of
 	// pubkeys returned from MsgKeySigners, and the order
@@ -49,25 +45,60 @@ type Tx interface {
 
 var _ Tx = (*StdTx)(nil)
 
-// StdTx is a standard way to wrap a Msg with Signatures.
+// StdTx is a standard way to wrap a Msg with Fee and Signatures.
 // NOTE: the first signature is the FeePayer (Signatures must not be nil).
 type StdTx struct {
 	Msg        `json:"msg"`
+	Fee        StdFee         `json:"fee"`
 	Signatures []StdSignature `json:"signatures"`
 }
 
-func NewStdTx(msg Msg, sigs []StdSignature) StdTx {
+func NewStdTx(msg Msg, fee StdFee, sigs []StdSignature) StdTx {
 	return StdTx{
 		Msg:        msg,
+		Fee:        fee,
 		Signatures: sigs,
 	}
 }
 
 //nolint
 func (tx StdTx) GetMsg() Msg                   { return tx.Msg }
-func (tx StdTx) GetFeePayer() Address          { return tx.Signatures[0].PubKey.Address() } // XXX but PubKey is optional!
 func (tx StdTx) GetSignatures() []StdSignature { return tx.Signatures }
 
+// FeePayer returns the address responsible for paying the fees
+// for the transactions. It's the first address returned by msg.GetSigners().
+// If GetSigners() is empty, this panics.
+func FeePayer(tx Tx) Address {
+	return tx.GetMsg().GetSigners()[0]
+}
+
+//__________________________________________________________
+
+// StdFee includes the amount of coins paid in fees and the maximum
+// gas to be used by the transaction. The ratio yields an effective "gasprice",
+// which must be above some miminum to be accepted into the mempool.
+type StdFee struct {
+	Amount Coins `json"amount"`
+	Gas    int64 `json"gas"`
+}
+
+func NewStdFee(gas int64, amount ...Coin) StdFee {
+	return StdFee{
+		Amount: amount,
+		Gas:    gas,
+	}
+}
+
+func (fee StdFee) Bytes() []byte {
+	bz, err := json.Marshal(fee) // TODO
+	if err != nil {
+		panic(err)
+	}
+	return bz
+}
+
+//__________________________________________________________
+
 // StdSignDoc is replay-prevention structure.
 // It includes the result of msg.GetSignBytes(),
 // as well as the ChainID (prevent cross chain replay)
@@ -76,27 +107,18 @@ func (tx StdTx) GetSignatures() []StdSignature { return tx.Signatures }
 type StdSignDoc struct {
 	ChainID   string  `json:"chain_id"`
 	Sequences []int64 `json:"sequences"`
+	FeeBytes  []byte  `json:"fee_bytes"`
 	MsgBytes  []byte  `json:"msg_bytes"`
-	AltBytes  []byte  `json:"alt_bytes"` // TODO: do we really want this ?
+	AltBytes  []byte  `json:"alt_bytes"`
 }
 
-// StdSignMsg is a convenience structure for passing along
-// a Msg with the other requirements for a StdSignDoc before
-// it is signed. For use in the CLI
-type StdSignMsg struct {
-	ChainID   string
-	Sequences []int64
-	Msg       Msg
-}
-
-func (msg StdSignMsg) Bytes() []byte {
-	return StdSignBytes(msg.ChainID, msg.Sequences, msg.Msg)
-}
-
-func StdSignBytes(chainID string, sequences []int64, msg Msg) []byte {
+// StdSignBytes returns the bytes to sign for a transaction.
+// TODO: change the API to just take a chainID and StdTx ?
+func StdSignBytes(chainID string, sequences []int64, fee StdFee, msg Msg) []byte {
 	bz, err := json.Marshal(StdSignDoc{
 		ChainID:   chainID,
 		Sequences: sequences,
+		FeeBytes:  fee.Bytes(),
 		MsgBytes:  msg.GetSignBytes(),
 	})
 	if err != nil {
@@ -105,7 +127,51 @@ func StdSignBytes(chainID string, sequences []int64, msg Msg) []byte {
 	return bz
 }
 
-//-------------------------------------
+// StdSignMsg is a convenience structure for passing along
+// a Msg with the other requirements for a StdSignDoc before
+// it is signed. For use in the CLI.
+type StdSignMsg struct {
+	ChainID   string
+	Sequences []int64
+	Fee       StdFee
+	Msg       Msg
+	// XXX: Alt
+}
+
+func (msg StdSignMsg) Bytes() []byte {
+	return StdSignBytes(msg.ChainID, msg.Sequences, msg.Fee, msg.Msg)
+}
+
+//__________________________________________________________
 
 // Application function variable used to unmarshal transaction bytes
 type TxDecoder func(txBytes []byte) (Tx, Error)
+
+//__________________________________________________________
+
+var _ Msg = (*TestMsg)(nil)
+
+// msg type for testing
+type TestMsg struct {
+	signers []Address
+}
+
+func NewTestMsg(addrs ...Address) *TestMsg {
+	return &TestMsg{
+		signers: addrs,
+	}
+}
+
+func (msg *TestMsg) Type() string                            { return "TestMsg" }
+func (msg *TestMsg) Get(key interface{}) (value interface{}) { return nil }
+func (msg *TestMsg) GetSignBytes() []byte {
+	bz, err := json.Marshal(msg.signers)
+	if err != nil {
+		panic(err)
+	}
+	return bz
+}
+func (msg *TestMsg) ValidateBasic() Error { return nil }
+func (msg *TestMsg) GetSigners() []Address {
+	return msg.signers
+}
diff --git a/types/tx_msg_test.go b/types/tx_msg_test.go
new file mode 100644
index 0000000000..f72cdea26e
--- /dev/null
+++ b/types/tx_msg_test.go
@@ -0,0 +1,30 @@
+package types
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	crypto "github.com/tendermint/go-crypto"
+)
+
+func newStdFee() StdFee {
+	return NewStdFee(100,
+		Coin{"atom", 150},
+	)
+}
+
+func TestStdTx(t *testing.T) {
+	priv := crypto.GenPrivKeyEd25519()
+	addr := priv.PubKey().Address()
+	msg := NewTestMsg(addr)
+	fee := newStdFee()
+	sigs := []StdSignature{}
+
+	tx := NewStdTx(msg, fee, sigs)
+	assert.Equal(t, msg, tx.GetMsg())
+	assert.Equal(t, sigs, tx.GetSignatures())
+
+	feePayer := FeePayer(tx)
+	assert.Equal(t, addr, feePayer)
+}
diff --git a/x/auth/ante.go b/x/auth/ante.go
index f2495af78d..43b9bb8341 100644
--- a/x/auth/ante.go
+++ b/x/auth/ante.go
@@ -1,12 +1,15 @@
 package auth
 
 import (
+	"bytes"
 	"fmt"
-	"reflect"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
+// NewAnteHandler returns an AnteHandler that checks
+// and increments sequence numbers, checks signatures,
+// and deducts fees from the first signer.
 func NewAnteHandler(accountMapper sdk.AccountMapper) sdk.AnteHandler {
 	return func(
 		ctx sdk.Context, tx sdk.Tx,
@@ -23,6 +26,12 @@ func NewAnteHandler(accountMapper sdk.AccountMapper) sdk.AnteHandler {
 		// TODO: can tx just implement message?
 		msg := tx.GetMsg()
 
+		// TODO: will this always be a stdtx? should that be used in the function signature?
+		stdTx, ok := tx.(sdk.StdTx)
+		if !ok {
+			return ctx, sdk.ErrInternal("tx must be sdk.StdTx").Result(), true
+		}
+
 		// Assert that number of signatures is correct.
 		var signerAddrs = msg.GetSigners()
 		if len(sigs) != len(signerAddrs) {
@@ -31,51 +40,64 @@ func NewAnteHandler(accountMapper sdk.AccountMapper) sdk.AnteHandler {
 				true
 		}
 
-		// Collect accounts to set in the context
-		var signerAccs = make([]sdk.Account, len(signerAddrs))
-
-		// Get the sign bytes by collecting all sequence numbers
+		// Get the sign bytes (requires all sequence numbers and the fee)
 		sequences := make([]int64, len(signerAddrs))
 		for i := 0; i < len(signerAddrs); i++ {
 			sequences[i] = sigs[i].Sequence
 		}
-		signBytes := sdk.StdSignBytes(ctx.ChainID(), sequences, msg)
+		fee := stdTx.Fee
+		signBytes := sdk.StdSignBytes(ctx.ChainID(), sequences, fee, msg)
 
-		// Check fee payer sig and nonce, and deduct fee.
-		// This is done first because it only
-		// requires fetching 1 account.
-		payerAddr, payerSig := signerAddrs[0], sigs[0]
-		payerAcc, res := processSig(ctx, accountMapper, payerAddr, payerSig, signBytes)
-		if !res.IsOK() {
-			return ctx, res, true
-		}
-		signerAccs[0] = payerAcc
-		// TODO: Charge fee from payerAcc.
-		// TODO: accountMapper.SetAccount(ctx, payerAddr)
-
-		// Check sig and nonce for the rest.
-		for i := 1; i < len(sigs); i++ {
+		// Check sig and nonce and collect signer accounts.
+		var signerAccs = make([]sdk.Account, len(signerAddrs))
+		for i := 0; i < len(sigs); i++ {
 			signerAddr, sig := signerAddrs[i], sigs[i]
-			signerAcc, res := processSig(ctx, accountMapper, signerAddr, sig, signBytes)
+
+			// check signature, return account with incremented nonce
+			signerAcc, res := processSig(
+				ctx, accountMapper,
+				signerAddr, sig, signBytes,
+			)
 			if !res.IsOK() {
 				return ctx, res, true
 			}
+
+			// first sig pays the fees
+			if i == 0 {
+				// TODO: min fee
+				if !fee.Amount.IsZero() {
+					signerAcc, res = deductFees(signerAcc, fee)
+					if !res.IsOK() {
+						return ctx, res, true
+					}
+				}
+			}
+
+			// Save the account.
+			accountMapper.SetAccount(ctx, signerAcc)
 			signerAccs[i] = signerAcc
 		}
 
+		// cache the signer accounts in the context
 		ctx = WithSigners(ctx, signerAccs)
+
+		// TODO: tx tags (?)
+
 		return ctx, sdk.Result{}, false // continue...
 	}
 }
 
 // verify the signature and increment the sequence.
-// if the account doesn't have a pubkey, set it as well.
-func processSig(ctx sdk.Context, am sdk.AccountMapper, addr sdk.Address, sig sdk.StdSignature, signBytes []byte) (acc sdk.Account, res sdk.Result) {
+// if the account doesn't have a pubkey, set it.
+func processSig(
+	ctx sdk.Context, am sdk.AccountMapper,
+	addr sdk.Address, sig sdk.StdSignature, signBytes []byte) (
+	acc sdk.Account, res sdk.Result) {
 
-	// Get the account
+	// Get the account.
 	acc = am.GetAccount(ctx, addr)
 	if acc == nil {
-		return nil, sdk.ErrUnrecognizedAddress(addr).Result()
+		return nil, sdk.ErrUnrecognizedAddress(addr.String()).Result()
 	}
 
 	// Check and increment sequence number.
@@ -86,20 +108,21 @@ func processSig(ctx sdk.Context, am sdk.AccountMapper, addr sdk.Address, sig sdk
 	}
 	acc.SetSequence(seq + 1)
 
-	// Check and possibly set pubkey.
+	// If pubkey is not known for account,
+	// set it from the StdSignature.
 	pubKey := acc.GetPubKey()
 	if pubKey.Empty() {
-		if sig.PubKey.Empty() {
-			return nil, sdk.ErrInternal("public Key not found").Result()
-		}
-		if !reflect.DeepEqual(sig.PubKey.Address(), addr) {
-			return nil, sdk.ErrInternal(
-				fmt.Sprintf("invalid PubKey for address %v", addr)).Result()
-		}
 		pubKey = sig.PubKey
+		if pubKey.Empty() {
+			return nil, sdk.ErrInvalidPubKey("PubKey not found").Result()
+		}
+		if !bytes.Equal(pubKey.Address(), addr) {
+			return nil, sdk.ErrInvalidPubKey(
+				fmt.Sprintf("PubKey does not match Signer address %v", addr)).Result()
+		}
 		err := acc.SetPubKey(pubKey)
 		if err != nil {
-			return nil, sdk.ErrInternal("setting PubKey on signer").Result()
+			return nil, sdk.ErrInternal("setting PubKey on signer's account").Result()
 		}
 	}
 	// Check sig.
@@ -107,7 +130,21 @@ func processSig(ctx sdk.Context, am sdk.AccountMapper, addr sdk.Address, sig sdk
 		return nil, sdk.ErrUnauthorized("signature verification failed").Result()
 	}
 
-	// Save the account.
-	am.SetAccount(ctx, acc)
 	return
 }
+
+// Deduct the fee from the account.
+// We could use the CoinKeeper (in addition to the AccountMapper,
+// because the CoinKeeper doesn't give us accounts), but it seems easier to do this.
+func deductFees(acc sdk.Account, fee sdk.StdFee) (sdk.Account, sdk.Result) {
+	coins := acc.GetCoins()
+	feeAmount := fee.Amount
+
+	newCoins := coins.Minus(feeAmount)
+	if !newCoins.IsNotNegative() {
+		errMsg := fmt.Sprintf("%s < %s", coins, feeAmount)
+		return nil, sdk.ErrInsufficientFunds(errMsg).Result()
+	}
+	acc.SetCoins(newCoins)
+	return acc, sdk.Result{}
+}
diff --git a/x/auth/ante_test.go b/x/auth/ante_test.go
index c3df2199d6..5bbb3d0b69 100644
--- a/x/auth/ante_test.go
+++ b/x/auth/ante_test.go
@@ -1,38 +1,32 @@
 package auth
 
 import (
-	"reflect"
 	"testing"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	abci "github.com/tendermint/abci/types"
 	crypto "github.com/tendermint/go-crypto"
 )
 
-// msg type for testing
-type testMsg struct {
-	signBytes []byte
-	signers   []sdk.Address
+func newTestMsg(addrs ...sdk.Address) *sdk.TestMsg {
+	return sdk.NewTestMsg(addrs...)
 }
 
-func newTestMsg(addrs ...sdk.Address) *testMsg {
-	return &testMsg{
-		signBytes: []byte(addrs[0]),
-		signers:   addrs,
+func newStdFee() sdk.StdFee {
+	return sdk.NewStdFee(100,
+		sdk.Coin{"atom", 150},
+	)
+}
+
+// coins to more than cover the fee
+func newCoins() sdk.Coins {
+	return sdk.Coins{
+		{"atom", 10000000},
 	}
 }
 
-func (msg *testMsg) Type() string                            { return "testMsg" }
-func (msg *testMsg) Get(key interface{}) (value interface{}) { return nil }
-func (msg *testMsg) GetSignBytes() []byte {
-	return msg.signBytes
-}
-func (msg *testMsg) ValidateBasic() sdk.Error { return nil }
-func (msg *testMsg) GetSigners() []sdk.Address {
-	return msg.signers
-}
-
 // generate a priv key and return it with its address
 func privAndAddr() (crypto.PrivKey, sdk.Address) {
 	priv := crypto.GenPrivKeyEd25519()
@@ -55,17 +49,18 @@ func checkInvalidTx(t *testing.T, anteHandler sdk.AnteHandler, ctx sdk.Context,
 	assert.Equal(t, code, result.Code)
 }
 
-func newTestTx(ctx sdk.Context, msg sdk.Msg, privs []crypto.PrivKey, seqs []int64) sdk.Tx {
-	signBytes := sdk.StdSignBytes(ctx.ChainID(), seqs, msg)
-	return newTestTxWithSignBytes(msg, privs, seqs, signBytes)
+func newTestTx(ctx sdk.Context, msg sdk.Msg, privs []crypto.PrivKey, seqs []int64, fee sdk.StdFee) sdk.Tx {
+	signBytes := sdk.StdSignBytes(ctx.ChainID(), seqs, fee, msg)
+	return newTestTxWithSignBytes(msg, privs, seqs, fee, signBytes)
 }
 
-func newTestTxWithSignBytes(msg sdk.Msg, privs []crypto.PrivKey, seqs []int64, signBytes []byte) sdk.Tx {
+func newTestTxWithSignBytes(msg sdk.Msg, privs []crypto.PrivKey, seqs []int64, fee sdk.StdFee, signBytes []byte) sdk.Tx {
 	sigs := make([]sdk.StdSignature, len(privs))
 	for i, priv := range privs {
 		sigs[i] = sdk.StdSignature{PubKey: priv.PubKey(), Signature: priv.Sign(signBytes), Sequence: seqs[i]}
 	}
-	return sdk.NewStdTx(msg, sigs)
+	tx := sdk.NewStdTx(msg, fee, sigs)
+	return tx
 }
 
 // Test various error cases in the AnteHandler control flow.
@@ -83,21 +78,26 @@ func TestAnteHandlerSigErrors(t *testing.T) {
 	// msg and signatures
 	var tx sdk.Tx
 	msg := newTestMsg(addr1, addr2)
+	fee := newStdFee()
 
 	// test no signatures
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{}, []int64{})
+	privs, seqs := []crypto.PrivKey{}, []int64{}
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
 	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeUnauthorized)
 
 	// test num sigs dont match GetSigners
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv1}, []int64{0})
+	privs, seqs = []crypto.PrivKey{priv1}, []int64{0}
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
 	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeUnauthorized)
 
 	// test an unrecognized account
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv1, priv2}, []int64{0, 0})
+	privs, seqs = []crypto.PrivKey{priv1, priv2}, []int64{0, 0}
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
 	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeUnrecognizedAddress)
 
 	// save the first account, but second is still unrecognized
 	acc1 := mapper.NewAccountWithAddress(ctx, addr1)
+	acc1.SetCoins(fee.Amount)
 	mapper.SetAccount(ctx, acc1)
 	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeUnrecognizedAddress)
 }
@@ -116,28 +116,34 @@ func TestAnteHandlerSequences(t *testing.T) {
 
 	// set the accounts
 	acc1 := mapper.NewAccountWithAddress(ctx, addr1)
+	acc1.SetCoins(newCoins())
 	mapper.SetAccount(ctx, acc1)
 	acc2 := mapper.NewAccountWithAddress(ctx, addr2)
+	acc2.SetCoins(newCoins())
 	mapper.SetAccount(ctx, acc2)
 
 	// msg and signatures
 	var tx sdk.Tx
 	msg := newTestMsg(addr1)
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv1}, []int64{0})
+	fee := newStdFee()
 
 	// test good tx from one signer
+	privs, seqs := []crypto.PrivKey{priv1}, []int64{0}
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
 	checkValidTx(t, anteHandler, ctx, tx)
 
 	// test sending it again fails (replay protection)
 	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeInvalidSequence)
 
 	// fix sequence, should pass
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv1}, []int64{1})
+	seqs = []int64{1}
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
 	checkValidTx(t, anteHandler, ctx, tx)
 
 	// new tx with another signer and correct sequences
 	msg = newTestMsg(addr1, addr2)
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv1, priv2}, []int64{2, 0})
+	privs, seqs = []crypto.PrivKey{priv1, priv2}, []int64{2, 0}
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
 	checkValidTx(t, anteHandler, ctx, tx)
 
 	// replay fails
@@ -145,16 +151,54 @@ func TestAnteHandlerSequences(t *testing.T) {
 
 	// tx from just second signer with incorrect sequence fails
 	msg = newTestMsg(addr2)
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv2}, []int64{0})
+	privs, seqs = []crypto.PrivKey{priv2}, []int64{0}
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
 	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeInvalidSequence)
 
 	// fix the sequence and it passes
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv2}, []int64{1})
+	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv2}, []int64{1}, fee)
 	checkValidTx(t, anteHandler, ctx, tx)
 
 	// another tx from both of them that passes
 	msg = newTestMsg(addr1, addr2)
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv1, priv2}, []int64{3, 2})
+	privs, seqs = []crypto.PrivKey{priv1, priv2}, []int64{3, 2}
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
+	checkValidTx(t, anteHandler, ctx, tx)
+}
+
+// Test logic around fee deduction.
+func TestAnteHandlerFees(t *testing.T) {
+	// setup
+	ms, capKey := setupMultiStore()
+	mapper := NewAccountMapper(capKey, &BaseAccount{})
+	anteHandler := NewAnteHandler(mapper)
+	ctx := sdk.NewContext(ms, abci.Header{ChainID: "mychainid"}, false, nil)
+
+	// keys and addresses
+	priv1, addr1 := privAndAddr()
+
+	// set the accounts
+	acc1 := mapper.NewAccountWithAddress(ctx, addr1)
+	mapper.SetAccount(ctx, acc1)
+
+	// msg and signatures
+	var tx sdk.Tx
+	msg := newTestMsg(addr1)
+	privs, seqs := []crypto.PrivKey{priv1}, []int64{0}
+	fee := sdk.NewStdFee(100,
+		sdk.Coin{"atom", 150},
+	)
+
+	// signer does not have enough funds to pay the fee
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
+	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeInsufficientFunds)
+
+	acc1.SetCoins(sdk.Coins{{"atom", 149}})
+	mapper.SetAccount(ctx, acc1)
+	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeInsufficientFunds)
+
+	acc1.SetCoins(sdk.Coins{{"atom", 150}})
+	mapper.SetAccount(ctx, acc1)
 	checkValidTx(t, anteHandler, ctx, tx)
 }
 
@@ -171,35 +215,63 @@ func TestAnteHandlerBadSignBytes(t *testing.T) {
 
 	// set the accounts
 	acc1 := mapper.NewAccountWithAddress(ctx, addr1)
+	acc1.SetCoins(newCoins())
 	mapper.SetAccount(ctx, acc1)
 	acc2 := mapper.NewAccountWithAddress(ctx, addr2)
+	acc2.SetCoins(newCoins())
 	mapper.SetAccount(ctx, acc2)
 
 	var tx sdk.Tx
+	msg := newTestMsg(addr1)
+	fee := newStdFee()
+	fee2 := newStdFee()
+	fee2.Gas += 100
+	fee3 := newStdFee()
+	fee3.Amount[0].Amount += 100
 
 	// test good tx and signBytes
-	msg := newTestMsg(addr1)
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv1}, []int64{0})
+	privs, seqs := []crypto.PrivKey{priv1}, []int64{0}
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
 	checkValidTx(t, anteHandler, ctx, tx)
 
-	// test invalid chain_id
-	tx = newTestTxWithSignBytes(msg, []crypto.PrivKey{priv1}, []int64{1}, sdk.StdSignBytes("", []int64{1}, msg))
-	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeUnauthorized)
-	// test wrong seqs
-	tx = newTestTxWithSignBytes(msg, []crypto.PrivKey{priv1}, []int64{1}, sdk.StdSignBytes(ctx.ChainID(), []int64{2}, msg))
-	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeUnauthorized)
-	// test wrong msg
-	tx = newTestTxWithSignBytes(msg, []crypto.PrivKey{priv1}, []int64{1}, sdk.StdSignBytes(ctx.ChainID(), []int64{1}, newTestMsg(addr2)))
-	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeUnauthorized)
+	chainID := ctx.ChainID()
+	chainID2 := chainID + "somemorestuff"
+	codeUnauth := sdk.CodeUnauthorized
+
+	cases := []struct {
+		chainID string
+		seqs    []int64
+		fee     sdk.StdFee
+		msg     sdk.Msg
+		code    sdk.CodeType
+	}{
+		{chainID2, []int64{1}, fee, msg, codeUnauth},               // test wrong chain_id
+		{chainID, []int64{2}, fee, msg, codeUnauth},                // test wrong seqs
+		{chainID, []int64{1, 2}, fee, msg, codeUnauth},             // test wrong seqs
+		{chainID, []int64{1}, fee, newTestMsg(addr2), codeUnauth},  // test wrong msg
+		{chainID, []int64{1}, fee2, newTestMsg(addr2), codeUnauth}, // test wrong fee
+		{chainID, []int64{1}, fee3, newTestMsg(addr2), codeUnauth}, // test wrong fee
+	}
+
+	privs, seqs = []crypto.PrivKey{priv1}, []int64{1}
+	for _, cs := range cases {
+		tx := newTestTxWithSignBytes(
+			msg, privs, seqs, fee,
+			sdk.StdSignBytes(cs.chainID, cs.seqs, cs.fee, cs.msg),
+		)
+		checkInvalidTx(t, anteHandler, ctx, tx, cs.code)
+	}
 
 	// test wrong signer if public key exist
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv2}, []int64{1})
+	privs, seqs = []crypto.PrivKey{priv2}, []int64{1}
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
 	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeUnauthorized)
 
 	// test wrong signer if public doesn't exist
 	msg = newTestMsg(addr2)
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv1}, []int64{0})
-	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeInternal)
+	privs, seqs = []crypto.PrivKey{priv1}, []int64{0}
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
+	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeInvalidPubKey)
 
 }
 
@@ -216,33 +288,37 @@ func TestAnteHandlerSetPubKey(t *testing.T) {
 
 	// set the accounts
 	acc1 := mapper.NewAccountWithAddress(ctx, addr1)
+	acc1.SetCoins(newCoins())
 	mapper.SetAccount(ctx, acc1)
 	acc2 := mapper.NewAccountWithAddress(ctx, addr2)
+	acc2.SetCoins(newCoins())
 	mapper.SetAccount(ctx, acc2)
 
 	var tx sdk.Tx
 
 	// test good tx and set public key
 	msg := newTestMsg(addr1)
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv1}, []int64{0})
+	privs, seqs := []crypto.PrivKey{priv1}, []int64{0}
+	fee := newStdFee()
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
 	checkValidTx(t, anteHandler, ctx, tx)
 
 	acc1 = mapper.GetAccount(ctx, addr1)
-	reflect.DeepEqual(acc1.GetPubKey(), priv1.PubKey())
+	require.Equal(t, acc1.GetPubKey(), priv1.PubKey())
 
 	// test public key not found
 	msg = newTestMsg(addr2)
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv1}, []int64{0})
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
 	sigs := tx.GetSignatures()
 	sigs[0].PubKey = crypto.PubKey{}
-	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeInternal)
+	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeInvalidPubKey)
 
 	acc2 = mapper.GetAccount(ctx, addr2)
 	assert.True(t, acc2.GetPubKey().Empty())
 
 	// test invalid signature and public key
-	tx = newTestTx(ctx, msg, []crypto.PrivKey{priv1}, []int64{0})
-	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeInternal)
+	tx = newTestTx(ctx, msg, privs, seqs, fee)
+	checkInvalidTx(t, anteHandler, ctx, tx, sdk.CodeInvalidPubKey)
 
 	acc2 = mapper.GetAccount(ctx, addr2)
 	assert.True(t, acc2.GetPubKey().Empty())
diff --git a/x/auth/baseaccount_test.go b/x/auth/baseaccount_test.go
index 85674af18b..b2f5b54ae2 100644
--- a/x/auth/baseaccount_test.go
+++ b/x/auth/baseaccount_test.go
@@ -11,42 +11,107 @@ import (
 	wire "github.com/cosmos/cosmos-sdk/wire"
 )
 
-func TestBaseAccount(t *testing.T) {
+func keyPubAddr() (crypto.PrivKey, crypto.PubKey, sdk.Address) {
 	key := crypto.GenPrivKeyEd25519()
 	pub := key.PubKey()
 	addr := pub.Address()
+	return key.Wrap(), pub, addr
+}
+
+func TestBaseAccountAddressPubKey(t *testing.T) {
+	_, pub1, addr1 := keyPubAddr()
+	_, pub2, addr2 := keyPubAddr()
+	acc := NewBaseAccountWithAddress(addr1)
+
+	// check the address (set) and pubkey (not set)
+	assert.EqualValues(t, addr1, acc.GetAddress())
+	assert.EqualValues(t, crypto.PubKey{}, acc.GetPubKey())
+
+	// can't override address
+	err := acc.SetAddress(addr2)
+	assert.NotNil(t, err)
+	assert.EqualValues(t, addr1, acc.GetAddress())
+
+	// set the pubkey
+	err = acc.SetPubKey(pub1)
+	assert.Nil(t, err)
+	assert.Equal(t, pub1, acc.GetPubKey())
+
+	// can't override pubkey
+	err = acc.SetPubKey(pub2)
+	assert.NotNil(t, err)
+	assert.Equal(t, pub1, acc.GetPubKey())
+
+	//------------------------------------
+
+	// can set address on empty account
+	acc2 := BaseAccount{}
+	err = acc2.SetAddress(addr2)
+	assert.Nil(t, err)
+	assert.EqualValues(t, addr2, acc2.GetAddress())
+}
+
+func TestBaseAccountCoins(t *testing.T) {
+	_, _, addr := keyPubAddr()
+	acc := NewBaseAccountWithAddress(addr)
+
+	someCoins := sdk.Coins{{"atom", 123}, {"eth", 246}}
+
+	err := acc.SetCoins(someCoins)
+	assert.Nil(t, err)
+	assert.Equal(t, someCoins, acc.GetCoins())
+}
+
+func TestBaseAccountSequence(t *testing.T) {
+	_, _, addr := keyPubAddr()
+	acc := NewBaseAccountWithAddress(addr)
+
+	seq := int64(7)
+
+	err := acc.SetSequence(seq)
+	assert.Nil(t, err)
+	assert.Equal(t, seq, acc.GetSequence())
+}
+
+func TestBaseAccountMarshal(t *testing.T) {
+	_, pub, addr := keyPubAddr()
+	acc := NewBaseAccountWithAddress(addr)
+
 	someCoins := sdk.Coins{{"atom", 123}, {"eth", 246}}
 	seq := int64(7)
 
-	acc := NewBaseAccountWithAddress(addr)
+	// set everything on the account
+	err := acc.SetPubKey(pub)
+	assert.Nil(t, err)
+	err = acc.SetSequence(seq)
+	assert.Nil(t, err)
+	err = acc.SetCoins(someCoins)
+	assert.Nil(t, err)
 
 	// need a codec for marshaling
 	codec := wire.NewCodec()
 	wire.RegisterCrypto(codec)
 
-	err := acc.SetPubKey(pub)
-	assert.Nil(t, err)
-	assert.Equal(t, pub, acc.GetPubKey())
-
-	assert.EqualValues(t, addr, acc.GetAddress())
-
-	err = acc.SetCoins(someCoins)
-	assert.Nil(t, err)
-	assert.Equal(t, someCoins, acc.GetCoins())
-
-	err = acc.SetSequence(seq)
-	assert.Nil(t, err)
-	assert.Equal(t, seq, acc.GetSequence())
-
 	b, err := codec.MarshalBinary(acc)
 	assert.Nil(t, err)
 
-	var acc2 BaseAccount
+	acc2 := BaseAccount{}
 	err = codec.UnmarshalBinary(b, &acc2)
 	assert.Nil(t, err)
 	assert.Equal(t, acc, acc2)
 
+	// error on bad bytes
 	acc2 = BaseAccount{}
 	err = codec.UnmarshalBinary(b[:len(b)/2], &acc2)
 	assert.NotNil(t, err)
+
+}
+
+func TestBaseAccountGetSet(t *testing.T) {
+	_, _, addr := keyPubAddr()
+	acc := NewBaseAccountWithAddress(addr)
+
+	// Get/Set are not yet defined - all values cause a panic.
+	assert.Panics(t, func() { acc.Get("key") })
+	assert.Panics(t, func() { acc.Set("key", "value") })
 }
diff --git a/x/auth/context.go b/x/auth/context.go
index 90de99f783..91259d9e6d 100644
--- a/x/auth/context.go
+++ b/x/auth/context.go
@@ -38,5 +38,9 @@ func WithSigners(ctx types.Context, accounts []types.Account) types.Context {
 }
 
 func GetSigners(ctx types.Context) []types.Account {
-	return ctx.Value(contextKeySigners).([]types.Account)
+	v := ctx.Value(contextKeySigners)
+	if v == nil {
+		return []types.Account{}
+	}
+	return v.([]types.Account)
 }
diff --git a/x/auth/context_test.go b/x/auth/context_test.go
new file mode 100644
index 0000000000..0e4db8b080
--- /dev/null
+++ b/x/auth/context_test.go
@@ -0,0 +1,39 @@
+package auth
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	abci "github.com/tendermint/abci/types"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+func TestContextWithSigners(t *testing.T) {
+	ms, _ := setupMultiStore()
+	ctx := sdk.NewContext(ms, abci.Header{ChainID: "mychainid"}, false, nil)
+
+	_, _, addr1 := keyPubAddr()
+	_, _, addr2 := keyPubAddr()
+	acc1 := NewBaseAccountWithAddress(addr1)
+	acc1.SetSequence(7132)
+	acc2 := NewBaseAccountWithAddress(addr2)
+	acc2.SetSequence(8821)
+
+	// new ctx has no signers
+	signers := GetSigners(ctx)
+	assert.Equal(t, 0, len(signers))
+
+	ctx2 := WithSigners(ctx, []sdk.Account{&acc1, &acc2})
+
+	// original context is unchanged
+	signers = GetSigners(ctx)
+	assert.Equal(t, 0, len(signers))
+
+	// new context has signers
+	signers = GetSigners(ctx2)
+	assert.Equal(t, 2, len(signers))
+	assert.Equal(t, acc1, *(signers[0].(*BaseAccount)))
+	assert.Equal(t, acc2, *(signers[1].(*BaseAccount)))
+}
diff --git a/x/bank/mapper.go b/x/bank/mapper.go
index 76e7f4e2f5..ab2e854202 100644
--- a/x/bank/mapper.go
+++ b/x/bank/mapper.go
@@ -20,7 +20,7 @@ func NewCoinKeeper(am sdk.AccountMapper) CoinKeeper {
 func (ck CoinKeeper) SubtractCoins(ctx sdk.Context, addr sdk.Address, amt sdk.Coins) (sdk.Coins, sdk.Error) {
 	acc := ck.am.GetAccount(ctx, addr)
 	if acc == nil {
-		return amt, sdk.ErrUnrecognizedAddress(addr)
+		return amt, sdk.ErrUnrecognizedAddress(addr.String())
 	}
 
 	coins := acc.GetCoins()