diff --git a/config.go b/config.go
index 33b6394..69c2f64 100644
--- a/config.go
+++ b/config.go
@@ -112,6 +112,12 @@ type YNAB struct {
 	// They'd still be unapproved until approved in YNAB.
 	Cleared string `envconfig:"YNAB_CLEARED" default:"uncleared"`
 
+	// SwapFlow changes inflow to outflow and vice versa for any account with a
+	// IBAN number in the list. This maybe be relevant for credit card accounts.
+	//
+	// Example: "DK9520000123456789,NO8330001234567"
+	SwapFlow []string `envconfig:"YNAB_SWAPFLOW"`
+
 	ImportID ImportID
 }
 
diff --git a/writer/ynab/ynab.go b/writer/ynab/ynab.go
index d773120..57e50ed 100644
--- a/writer/ynab/ynab.go
+++ b/writer/ynab/ynab.go
@@ -94,7 +94,6 @@ func ynabberToYNAB(cfg ynabber.Config, t ynabber.Transaction) (Ytransaction, err
 	}
 
 	date := t.Date.Format("2006-01-02")
-	amount := t.Amount.String()
 
 	// Trim consecutive spaces from memo and truncate if too long
 	memo := strings.TrimSpace(space.ReplaceAllString(t.Memo, " "))
@@ -112,11 +111,21 @@ func ynabberToYNAB(cfg ynabber.Config, t ynabber.Transaction) (Ytransaction, err
 		payee = payee[0:(maxPayeeSize - 1)]
 	}
 
+	// If SwapFlow is defined check if the account is configured to swap inflow
+	// to outflow. If so swap it by using the Negate method.
+	if cfg.YNAB.SwapFlow != nil {
+		for _, account := range cfg.YNAB.SwapFlow {
+			if account == t.Account.IBAN {
+				t.Amount = t.Amount.Negate()
+			}
+		}
+	}
+
 	return Ytransaction{
 		ImportID:  importIDMaker(cfg, t),
 		AccountID: accountID,
 		Date:      date,
-		Amount:    amount,
+		Amount:    t.Amount.String(),
 		PayeeName: payee,
 		Memo:      memo,
 		Cleared:   cfg.YNAB.Cleared,
diff --git a/writer/ynab/ynab_test.go b/writer/ynab/ynab_test.go
index 71cab38..335f9ff 100644
--- a/writer/ynab/ynab_test.go
+++ b/writer/ynab/ynab_test.go
@@ -1,6 +1,7 @@
 package ynab
 
 import (
+	"reflect"
 	"testing"
 	"time"
 
@@ -106,3 +107,74 @@ func TestAccountParser(t *testing.T) {
 		})
 	}
 }
+
+func TestYnabberToYNAB(t *testing.T) {
+	type args struct {
+		cfg ynabber.Config
+		t   ynabber.Transaction
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    Ytransaction
+		wantErr bool
+	}{
+		{
+			name: "Default",
+			args: args{
+				cfg: ynabber.Config{
+					YNAB: ynabber.YNAB{
+						AccountMap: map[string]string{"foobar": "abc"},
+					},
+				},
+				t: ynabber.Transaction{
+					Account: ynabber.Account{IBAN: "foobar"},
+					Amount:  10000,
+				},
+			},
+			want: Ytransaction{
+				AccountID: "abc",
+				Date:      "0001-01-01",
+				Amount:    "10000",
+				ImportID:  "YBBR:e066d58050f67a602720e5f123f",
+				Approved:  false,
+			},
+			wantErr: false,
+		},
+		{
+			name: "SwapFlow",
+			args: args{
+				cfg: ynabber.Config{
+					YNAB: ynabber.YNAB{
+						SwapFlow:   []string{"foobar"},
+						AccountMap: map[string]string{"foobar": "abc"},
+					},
+				},
+				t: ynabber.Transaction{
+					Account: ynabber.Account{IBAN: "foobar"},
+					Amount:  10000,
+				},
+			},
+			want: Ytransaction{
+				AccountID: "abc",
+				Date:      "0001-01-01",
+				Amount:    "-10000",
+				ImportID:  "YBBR:2e18b15a1a51f0c2278147a4ca5",
+				Approved:  false,
+			},
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ynabberToYNAB(tt.args.cfg, tt.args.t)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ynabberToYNAB() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("ynabberToYNAB() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
diff --git a/ynabber.go b/ynabber.go
index d9901a6..20c94a5 100644
--- a/ynabber.go
+++ b/ynabber.go
@@ -27,6 +27,11 @@ func (p Payee) Strip(s []string) Payee {
 
 type Milliunits int64
 
+// Negate changes the sign of m to the opposite
+func (m Milliunits) Negate() Milliunits {
+	return m * -1
+}
+
 type Transaction struct {
 	Account Account
 	ID      ID