diff --git a/go.mod b/go.mod
index 0299eeca..cce317eb 100644
--- a/go.mod
+++ b/go.mod
@@ -16,6 +16,7 @@ require (
 	github.com/kr/pretty v0.2.0 // indirect
 	github.com/lucasjones/reggen v0.0.0-20180717132126-cdb49ff09d77
 	github.com/mitchellh/mapstructure v1.3.3
+	github.com/neilotoole/errgroup v0.1.5
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/segmentio/fasthash v1.0.3
 	github.com/stretchr/objx v0.1.1 // indirect
diff --git a/go.sum b/go.sum
index a5b7b9f5..6757e455 100644
--- a/go.sum
+++ b/go.sum
@@ -193,6 +193,8 @@ github.com/mitchellh/mapstructure v1.3.3 h1:SzB1nHZ2Xi+17FP0zVQBHIZqvwRN9408fJO8
 github.com/mitchellh/mapstructure v1.3.3/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
 github.com/naoina/go-stringutil v0.1.0/go.mod h1:XJ2SJL9jCtBh+P9q5btrd/Ylo8XwT/h1USek5+NqSA0=
 github.com/naoina/toml v0.1.2-0.20170918210437-9fafd6967416/go.mod h1:NBIhNtsFMo3G2szEBne+bO4gS192HuIYRqfvOWb4i1E=
+github.com/neilotoole/errgroup v0.1.5 h1:DxEGoIfFm5ooGicidR+okiHjoOaGRKFaSxDPVZuuu2I=
+github.com/neilotoole/errgroup v0.1.5/go.mod h1:Q2nLGf+594h0CLBs/Mbg6qOr7GtqDK7C2S41udRnToE=
 github.com/nxadm/tail v1.4.4/go.mod h1:kenIhsEOeOJmVchQTgglprH7qJGnHDVpk1VPCcaMI8A=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=
 github.com/olekukonko/tablewriter v0.0.1/go.mod h1:vsDQFd/mU46D+Z4whnwzcISnGGzXWMclvtLoiIKAKIo=
diff --git a/parser/balance_changes.go b/parser/balance_changes.go
index 9b6c01bd..69d23c46 100644
--- a/parser/balance_changes.go
+++ b/parser/balance_changes.go
@@ -128,9 +128,11 @@ func (p *Parser) BalanceChanges(
 		}
 	}
 
-	allChanges := []*BalanceChange{}
+	i := 0
+	allChanges := make([]*BalanceChange, len(balanceChanges))
 	for _, change := range balanceChanges {
-		allChanges = append(allChanges, change)
+		allChanges[i] = change
+		i++
 	}
 
 	return allChanges, nil
diff --git a/storage/modules/balance_storage.go b/storage/modules/balance_storage.go
index c4705451..5aff76bb 100644
--- a/storage/modules/balance_storage.go
+++ b/storage/modules/balance_storage.go
@@ -22,7 +22,7 @@ import (
 	"math/big"
 	"sync"
 
-	"golang.org/x/sync/errgroup"
+	"github.com/neilotoole/errgroup"
 
 	"github.com/coinbase/rosetta-sdk-go/asserter"
 	"github.com/coinbase/rosetta-sdk-go/parser"
@@ -194,7 +194,8 @@ func (b *BalanceStorage) AddingBlock(
 	var newAccounts int
 	var newAccountsLock sync.Mutex
 
-	g, gctx := errgroup.WithContext(ctx)
+	// Concurrent execution limited to runtime.NumCPU
+	g, gctx := errgroup.WithContextN(ctx, 0, 0)
 	for i := range changes {
 		// We need to set variable before calling goroutine
 		// to avoid getting an updated pointer as loop iteration
@@ -268,7 +269,8 @@ func (b *BalanceStorage) RemovingBlock(
 	staleAccounts := []*types.AccountCurrency{}
 	var staleAccountsMutex sync.Mutex
 
-	g, gctx := errgroup.WithContext(ctx)
+	// Concurrent execution limited to runtime.NumCPU
+	g, gctx := errgroup.WithContextN(ctx, 0, 0)
 	for i := range changes {
 		// We need to set variable before calling goroutine
 		// to avoid getting an updated pointer as loop iteration