Why Taxes are due on 30.9. in ZH?

[Your_Full_Name]

@dr.coffee

My understanding of the ZH tax puzzle (of course I only moved there last year):

+1% p.a. interest on everything you pay them voluntarily till 30.9.

-1% p.a. interest on everything short of the definitive tax bill after 30.9.

-4.5% p.a. on everything that you owe after the due date of the definitive tax bill.

This is what the city of Zurich says: Definitive Rechnung / Schlussrechnung - Stadt Zürich

Seems in line with what you state.

[Your_Full_Name]

BTW, people were already confused back then when Switzerland moved to Gegenwartsbesteuerung back in the early 2000s (Zurich apparently already switched in 1999).

Here’s the corresponding NZZ article from March 2002: Die Konfusion mit den Steuern | NZZ

The 1% interest you owe (get paid) today was 2% back then.