diff --git a/x/auth/tx/builder.go b/x/auth/tx/builder.go
index 857d34a08a5..d29e805ad70 100644
--- a/x/auth/tx/builder.go
+++ b/x/auth/tx/builder.go
@@ -60,6 +60,10 @@ func newBuilder(pubkeyCodec types.PublicKeyCodec) *builder {
 }
 
 func (t *builder) GetMsgs() []sdk.Msg {
+	if t.tx == nil || t.tx.Body == nil {
+		return nil
+	}
+
 	anys := t.tx.Body.Messages
 	res := make([]sdk.Msg, len(anys))
 	for i, any := range anys {
diff --git a/x/auth/tx/builder_test.go b/x/auth/tx/builder_test.go
index c115f474ac8..f1a7b1140f1 100644
--- a/x/auth/tx/builder_test.go
+++ b/x/auth/tx/builder_test.go
@@ -110,6 +110,11 @@ func TestTxBuilder(t *testing.T) {
 	require.Equal(t, len(msgs), len(tx.GetMsgs()))
 	require.Equal(t, 1, len(tx.GetPubKeys()))
 	require.Equal(t, pubkey.Bytes(), tx.GetPubKeys()[0].Bytes())
+
+	tx = &builder{}
+	require.NotPanics(t, func() {
+		_ = tx.GetMsgs()
+	})
 }
 
 func TestBuilderValidateBasic(t *testing.T) {
diff --git a/x/genutil/types/codec.go b/x/genutil/types/codec.go
deleted file mode 100644
index 57e2115d072..00000000000
--- a/x/genutil/types/codec.go
+++ /dev/null
@@ -1,23 +0,0 @@
-package types
-
-import (
-	"github.com/cosmos/cosmos-sdk/codec"
-	cryptocodec "github.com/cosmos/cosmos-sdk/crypto/codec"
-	sdk "github.com/cosmos/cosmos-sdk/types"
-	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
-	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
-)
-
-// ModuleCdc defines a generic sealed codec to be used throughout this module
-var ModuleCdc *codec.Codec
-
-// TODO: abstract genesis transactions registration back to staking
-// required for genesis transactions
-func init() {
-	ModuleCdc = codec.New()
-	stakingtypes.RegisterCodec(ModuleCdc)
-	authtypes.RegisterCodec(ModuleCdc)
-	sdk.RegisterCodec(ModuleCdc)
-	cryptocodec.RegisterCrypto(ModuleCdc)
-	ModuleCdc.Seal()
-}
diff --git a/x/genutil/types/genesis_state.go b/x/genutil/types/genesis_state.go
index 034f6737795..2e801da76a4 100644
--- a/x/genutil/types/genesis_state.go
+++ b/x/genutil/types/genesis_state.go
@@ -38,10 +38,14 @@ func DefaultGenesisState() GenesisState {
 
 // NewGenesisStateFromTx creates a new GenesisState object
 // from auth transactions
-func NewGenesisStateFromTx(genTxs []sdk.Tx) GenesisState {
+func NewGenesisStateFromTx(txJSONEncoder sdk.TxEncoder, genTxs []sdk.Tx) GenesisState {
 	genTxsBz := make([]json.RawMessage, len(genTxs))
 	for i, genTx := range genTxs {
-		genTxsBz[i] = ModuleCdc.MustMarshalJSON(genTx)
+		var err error
+		genTxsBz[i], err = txJSONEncoder(genTx)
+		if err != nil {
+			panic(err)
+		}
 	}
 	return NewGenesisState(genTxsBz)
 }
diff --git a/x/genutil/types/genesis_state_test.go b/x/genutil/types/genesis_state_test.go
index 3be955e610d..2da26fa0b77 100644
--- a/x/genutil/types/genesis_state_test.go
+++ b/x/genutil/types/genesis_state_test.go
@@ -9,7 +9,6 @@ import (
 	"github.com/tendermint/tendermint/crypto/ed25519"
 
 	"github.com/cosmos/cosmos-sdk/simapp"
-	"github.com/cosmos/cosmos-sdk/simapp/params"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/genutil/types"
 	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
@@ -42,13 +41,13 @@ func TestValidateGenesisMultipleMessages(t *testing.T) {
 	msg2 := stakingtypes.NewMsgCreateValidator(sdk.ValAddress(pk2.Address()), pk2,
 		sdk.NewInt64Coin(sdk.DefaultBondDenom, 50), desc, comm, sdk.OneInt())
 
-	txGen := params.MakeEncodingConfig().TxConfig
+	txGen := simapp.MakeEncodingConfig().TxConfig
 	txBuilder := txGen.NewTxBuilder()
 	err := txBuilder.SetMsgs(msg1, msg2)
 	require.NoError(t, err)
 
 	tx := txBuilder.GetTx()
-	genesisState := types.NewGenesisStateFromTx([]sdk.Tx{tx})
+	genesisState := types.NewGenesisStateFromTx(txGen.TxJSONEncoder(), []sdk.Tx{tx})
 
 	err = types.ValidateGenesis(genesisState, simapp.MakeEncodingConfig().TxConfig.TxJSONDecoder())
 	require.Error(t, err)
@@ -59,13 +58,13 @@ func TestValidateGenesisBadMessage(t *testing.T) {
 
 	msg1 := stakingtypes.NewMsgEditValidator(sdk.ValAddress(pk1.Address()), desc, nil, nil)
 
-	txGen := params.MakeEncodingConfig().TxConfig
+	txGen := simapp.MakeEncodingConfig().TxConfig
 	txBuilder := txGen.NewTxBuilder()
 	err := txBuilder.SetMsgs(msg1)
 	require.NoError(t, err)
 
 	tx := txBuilder.GetTx()
-	genesisState := types.NewGenesisStateFromTx([]sdk.Tx{tx})
+	genesisState := types.NewGenesisStateFromTx(txGen.TxJSONEncoder(), []sdk.Tx{tx})
 
 	err = types.ValidateGenesis(genesisState, simapp.MakeEncodingConfig().TxConfig.TxJSONDecoder())
 	require.Error(t, err)