diff --git a/chain/actors/actor_multisig.go b/chain/actors/actor_multisig.go
index 765f13b4c..2b2c5dec5 100644
--- a/chain/actors/actor_multisig.go
+++ b/chain/actors/actor_multisig.go
@@ -14,10 +14,11 @@ func init() {
 	cbor.RegisterCborType(MultiSigConstructorParams{})
 	cbor.RegisterCborType(MultiSigProposeParams{})
 	cbor.RegisterCborType(MultiSigTxID{})
-	cbor.RegisterCborType(MultiSigSigner{})
 	cbor.RegisterCborType(MultiSigSwapSignerParams{})
 	cbor.RegisterCborType(MultiSigChangeReqParams{})
 	cbor.RegisterCborType(MTransaction{})
+	cbor.RegisterCborType(MultiSigRemoveSignerParam{})
+	cbor.RegisterCborType(MultiSigAddSignerParam{})
 }
 
 type MultiSigActor struct{}
@@ -262,12 +263,13 @@ func (msa MultiSigActor) Cancel(act *types.Actor, vmctx types.VMContext,
 	return nil, msa.save(vmctx, head, self)
 }
 
-type MultiSigSigner struct {
-	Signer address.Address
+type MultiSigAddSignerParam struct {
+	Signer   address.Address
+	Increase bool
 }
 
 func (msa MultiSigActor) AddSigner(act *types.Actor, vmctx types.VMContext,
-	params *MultiSigSigner) ([]byte, ActorError) {
+	params *MultiSigAddSignerParam) ([]byte, ActorError) {
 
 	head, self, err := msa.load(vmctx)
 	if err != nil {
@@ -281,13 +283,22 @@ func (msa MultiSigActor) AddSigner(act *types.Actor, vmctx types.VMContext,
 	if self.isSigner(params.Signer) {
 		return nil, aerrors.New(5, "new address is already a signer")
 	}
+
 	self.Signers = append(self.Signers, params.Signer)
+	if params.Increase {
+		self.Required = self.Required + 1
+	}
 
 	return nil, msa.save(vmctx, head, self)
 }
 
+type MultiSigRemoveSignerParam struct {
+	Signer   address.Address
+	Decrease bool
+}
+
 func (msa MultiSigActor) RemoveSigner(act *types.Actor, vmctx types.VMContext,
-	params *MultiSigSigner) ([]byte, ActorError) {
+	params *MultiSigRemoveSignerParam) ([]byte, ActorError) {
 
 	head, self, err := msa.load(vmctx)
 	if err != nil {
@@ -308,6 +319,10 @@ func (msa MultiSigActor) RemoveSigner(act *types.Actor, vmctx types.VMContext,
 			newSigners = append(newSigners, s)
 		}
 	}
+	if params.Decrease || uint32(len(self.Signers)-1) < self.Required {
+		self.Required = self.Required - 1
+	}
+
 	self.Signers = newSigners
 
 	return nil, msa.save(vmctx, head, self)
diff --git a/chain/actors/actor_multisig_test.go b/chain/actors/actor_multisig_test.go
index 57be8666c..8dc636f2d 100644
--- a/chain/actors/actor_multisig_test.go
+++ b/chain/actors/actor_multisig_test.go
@@ -53,7 +53,7 @@ func TestMultiSigOps(t *testing.T) {
 		HarnessAddr(&creatorAddr, 10000),
 		HarnessAddr(&sig1Addr, 10000),
 		HarnessAddr(&sig2Addr, 10000),
-		HarnessAddr(&outsideAddr, 0),
+		HarnessAddr(&outsideAddr, 1000),
 		HarnessActor(&multSigAddr, &creatorAddr, actors.MultisigActorCodeCid,
 			func() interface{} {
 				return actors.MultiSigConstructorParams{
@@ -66,6 +66,7 @@ func TestMultiSigOps(t *testing.T) {
 	curVal := types.NewInt(2000)
 	h := NewHarness2(t, opts...)
 	{
+		// Send funds into the multisig
 		ret, state := h.SendFunds(t, creatorAddr, multSigAddr, curVal)
 		ApplyOK(t, ret)
 		ms, err := state.GetActor(multSigAddr)
@@ -74,6 +75,7 @@ func TestMultiSigOps(t *testing.T) {
 	}
 
 	{
+		// Transfer funds outside of multsig
 		sendVal := types.NewInt(100)
 		ret, _ := h.Invoke(t, creatorAddr, multSigAddr, actors.MultiSigMethods.Propose,
 			actors.MultiSigProposeParams{
@@ -84,14 +86,19 @@ func TestMultiSigOps(t *testing.T) {
 		var txIDParam actors.MultiSigTxID
 		err := cbor.DecodeInto(ret.Return, &txIDParam.TxID)
 		assert.NoError(t, err, "decoding txid")
+
+		ret, _ = h.Invoke(t, outsideAddr, multSigAddr, actors.MultiSigMethods.Approve,
+			txIDParam)
+		assert.Equal(t, uint8(1), ret.ExitCode, "outsideAddr should not approve")
+
 		ret, state := h.Invoke(t, sig1Addr, multSigAddr, actors.MultiSigMethods.Approve,
 			txIDParam)
+		outAct, err := state.GetActor(outsideAddr)
 		ApplyOK(t, ret)
 		curVal = types.BigSub(curVal, sendVal)
 
-		outAct, err := state.GetActor(outsideAddr)
 		assert.NoError(t, err)
-		assert.Equal(t, sendVal, outAct.Balance)
+		assert.Equal(t, types.NewInt(1099), outAct.Balance)
 
 		msAct, err := state.GetActor(multSigAddr)
 		assert.NoError(t, err)
diff --git a/chain/vm/vm.go b/chain/vm/vm.go
index 95110b6f0..1ec5c184a 100644
--- a/chain/vm/vm.go
+++ b/chain/vm/vm.go
@@ -242,7 +242,7 @@ func (vm *VM) ApplyMessage(ctx context.Context, msg *types.Message) (*ApplyRet,
 	gascost := types.BigMul(msg.GasLimit, msg.GasPrice)
 	totalCost := types.BigAdd(gascost, msg.Value)
 	if types.BigCmp(fromActor.Balance, totalCost) < 0 {
-		return nil, xerrors.Errorf("not enough funds")
+		return nil, xerrors.Errorf("not enough funds (%s < %s)", fromActor.Balance, totalCost)
 	}
 	if err := DeductFunds(fromActor, gascost); err != nil {
 		return nil, xerrors.Errorf("failed to deduct funds: %w", err)