diff --git a/api/api_full.go b/api/api_full.go
index 80edf385b..5ff417dfd 100644
--- a/api/api_full.go
+++ b/api/api_full.go
@@ -122,6 +122,8 @@ type FullNode interface {
 	StateMinerSectorCount(context.Context, address.Address, *types.TipSet) (MinerSectors, error)
 	StateCompute(context.Context, uint64, []*types.Message, *types.TipSet) (cid.Cid, error)
 
+	MsigGetAvailableBalance(context.Context, address.Address, *types.TipSet) (types.BigInt, error)
+
 	MarketEnsureAvailable(context.Context, address.Address, types.BigInt) error
 	// MarketFreeBalance
 
diff --git a/api/apistruct/struct.go b/api/apistruct/struct.go
index 1a6e09421..57a0d9707 100644
--- a/api/apistruct/struct.go
+++ b/api/apistruct/struct.go
@@ -118,6 +118,8 @@ type FullNodeStruct struct {
 		StateListMessages             func(ctx context.Context, match *types.Message, ts *types.TipSet, toht uint64) ([]cid.Cid, error) `perm:"read"`
 		StateCompute                  func(context.Context, uint64, []*types.Message, *types.TipSet) (cid.Cid, error)                   `perm:"read"`
 
+		MsigGetAvailableBalance func(context.Context, address.Address, *types.TipSet) (types.BigInt, error) `perm:"read"`
+
 		MarketEnsureAvailable func(context.Context, address.Address, types.BigInt) error `perm:"sign"`
 
 		PaychGet                   func(ctx context.Context, from, to address.Address, ensureFunds types.BigInt) (*api.ChannelInfo, error)   `perm:"sign"`
@@ -477,6 +479,10 @@ func (c *FullNodeStruct) StateCompute(ctx context.Context, height uint64, msgs [
 	return c.Internal.StateCompute(ctx, height, msgs, ts)
 }
 
+func (c *FullNodeStruct) MsigGetAvailableBalance(ctx context.Context, a address.Address, ts *types.TipSet) (types.BigInt, error) {
+	return c.Internal.MsigGetAvailableBalance(ctx, a, ts)
+}
+
 func (c *FullNodeStruct) MarketEnsureAvailable(ctx context.Context, addr address.Address, amt types.BigInt) error {
 	return c.Internal.MarketEnsureAvailable(ctx, addr, amt)
 }
diff --git a/node/impl/full/state.go b/node/impl/full/state.go
index 3ba0dfbf8..c505c6efc 100644
--- a/node/impl/full/state.go
+++ b/node/impl/full/state.go
@@ -3,6 +3,7 @@ package full
 import (
 	"bytes"
 	"context"
+	"fmt"
 	"strconv"
 
 	"github.com/filecoin-project/go-amt-ipld"
@@ -404,3 +405,32 @@ func (a *StateAPI) StateListMessages(ctx context.Context, match *types.Message,
 func (a *StateAPI) StateCompute(ctx context.Context, height uint64, msgs []*types.Message, ts *types.TipSet) (cid.Cid, error) {
 	return stmgr.ComputeState(ctx, a.StateManager, height, msgs, ts)
 }
+
+func (a *StateAPI) MsigGetAvailableBalance(ctx context.Context, addr address.Address, ts *types.TipSet) (types.BigInt, error) {
+	if ts == nil {
+		ts = a.Chain.GetHeaviestTipSet()
+	}
+
+	var st actors.MultiSigActorState
+	act, err := a.StateManager.LoadActorState(ctx, addr, &st, ts)
+	if err != nil {
+		return types.EmptyInt, xerrors.Errorf("failed to load multisig actor state: %w", err)
+	}
+
+	if act.Code != actors.MultisigCodeCid {
+		return types.EmptyInt, fmt.Errorf("given actor was not a multisig")
+	}
+
+	if st.UnlockDuration == 0 {
+		return act.Balance, nil
+	}
+
+	offset := ts.Height() - st.StartingBlock
+	if offset > st.UnlockDuration {
+		return act.Balance, nil
+	}
+
+	minBalance := types.BigDiv(st.InitialBalance, types.NewInt(st.UnlockDuration))
+	minBalance = types.BigMul(minBalance, types.NewInt(offset))
+	return types.BigSub(act.Balance, minBalance), nil
+}