diff --git a/x/auth/tx/builder.go b/x/auth/tx/builder.go
index 7cf3596f342b..d64c927e6524 100644
--- a/x/auth/tx/builder.go
+++ b/x/auth/tx/builder.go
@@ -287,11 +287,17 @@ func (w *wrapper) SetSignatures(signatures ...signing.SignatureV2) error {
 	rawSigs := make([][]byte, n)
 
 	for i, sig := range signatures {
-		var modeInfo *tx.ModeInfo
+		var (
+			modeInfo *tx.ModeInfo
+			any      *codectypes.Any
+			err      error
+		)
 		modeInfo, rawSigs[i] = SignatureDataToModeInfoAndSig(sig.Data)
-		any, err := codectypes.NewAnyWithValue(sig.PubKey)
-		if err != nil {
-			return err
+		if sig.PubKey != nil {
+			any, err = codectypes.NewAnyWithValue(sig.PubKey)
+			if err != nil {
+				return err
+			}
 		}
 		signerInfos[i] = &tx.SignerInfo{
 			PublicKey: any,