diff --git a/frontend/src/components/Contributions/ContributionForm.spec.js b/frontend/src/components/Contributions/ContributionForm.spec.js
index 8f35948f9..e85a94884 100644
--- a/frontend/src/components/Contributions/ContributionForm.spec.js
+++ b/frontend/src/components/Contributions/ContributionForm.spec.js
@@ -109,8 +109,8 @@ describe('ContributionForm', () => {
           })
 
           describe('minimalDate', () => {
-            it('has "2020-06-01T00:00:00.000Z"', () => {
-              expect(wrapper.vm.minimalDate.toISOString()).toBe('2020-06-01T00:00:00.000Z')
+            it('has "2020-05-01T00:00:00.000Z"', () => {
+              expect(wrapper.vm.minimalDate.toISOString()).toBe('2020-05-01T00:00:00.000Z')
             })
           })
 
@@ -136,8 +136,8 @@ describe('ContributionForm', () => {
           })
 
           describe('minimalDate', () => {
-            it('has "2020-06-01T00:00:00.000Z"', () => {
-              expect(wrapper.vm.minimalDate.toISOString()).toBe('2020-06-01T00:00:00.000Z')
+            it('has "2020-05-01T00:00:00.000Z"', () => {
+              expect(wrapper.vm.minimalDate.toISOString()).toBe('2020-05-01T00:00:00.000Z')
             })
           })
 
@@ -159,8 +159,8 @@ describe('ContributionForm', () => {
           })
 
           describe('minimalDate', () => {
-            it('has "2019-12-01T00:00:00.000Z"', () => {
-              expect(wrapper.vm.minimalDate.toISOString()).toBe('2019-12-01T00:00:00.000Z')
+            it('has "2019-11-01T00:00:00.000Z"', () => {
+              expect(wrapper.vm.minimalDate.toISOString()).toBe('2019-11-01T00:00:00.000Z')
             })
           })
 
@@ -186,8 +186,8 @@ describe('ContributionForm', () => {
           })
 
           describe('minimalDate', () => {
-            it('has "2019-12-01T00:00:00.000Z"', () => {
-              expect(wrapper.vm.minimalDate.toISOString()).toBe('2019-12-01T00:00:00.000Z')
+            it('has "2019-11-01T00:00:00.000Z"', () => {
+              expect(wrapper.vm.minimalDate.toISOString()).toBe('2019-11-01T00:00:00.000Z')
             })
           })
 
diff --git a/frontend/src/components/Contributions/ContributionForm.vue b/frontend/src/components/Contributions/ContributionForm.vue
index 71593f2b1..bb8a1902f 100644
--- a/frontend/src/components/Contributions/ContributionForm.vue
+++ b/frontend/src/components/Contributions/ContributionForm.vue
@@ -134,7 +134,7 @@ export default {
       // sets the date to the 1st of the previous month
       let date = new Date(this.maximalDate) // has to be a new object, because of 'setMonth' changes the objects date
       date = new Date(date.setMonth(date.getMonth() - 1))
-      return new Date(date.getFullYear(), date.getMonth(), 1)
+      return new Date(date.getFullYear(), date.getMonth() - 1)
     },
     disabled() {
       return (