Hi
I have done my search on the forum, and it seems that most of the questions and answers are based on the duration of stay more than 1 year in Switzerland.

so my question is: What happens if I wish to leave Switzerland within a year as a non-EU?

This is the info I've gathered and please feel free to correct me if I got it wrong
but still got quite a lot of questions if you don't mind helping:

Lease:
The minimum stay is for a year, so if I wish to cancel it, I will need to send a registered mail by 1 July to cancel the lease as 30 Sept.
or I will need to find someone to take over the lease.

- what should I write in the cancellation of lease? is there a formal template that I will need to follow?
- what language should I write the cancellation in? as a formal cancellation, is English considered valid (since its not the official language in Switzerland) or do I have to provide German version as well?
- what happens to the Nebenkosten? will I only get the adjustment back as at calendar year end or lease end?

Bank accounts / Credit cards:
Credit card will be cancelled, bank accounts may be terminated, but depends on the bank, right?

Bills and Utilities:
Cancel all the utilities and bills, not sure how much notice I will need to give? Like 1 month?

De-registration:
Does this mean I will need to de-register at the local stadt office (I guess they will be notified once my lease is cancelled)? anywhere else I will need to de-register?

Pension Fund:
Pillar 1: will remain with the pension investment fund until I am retired
Pillar 2 and Pillar 3: I can cash out but will be taxed

- what happened to pillar 1 if there will be no more contributions? I will still need to wait until I am retired even though I am leaving the country?
- what if I decided not to cash out pillar 2 and 3 until years later?

Tax
Since I have only been here less than a year and always get taxed at source, should I still do my tax return?
Would the tax rate changed if I cashed out my Pillar 2 and 3 later as a non-resident?

Visa
I only have the L permit, how many days I can stay legally after my permit expires?

Apologies for many questions I have, I got a reloaction agent to help me when I started, but I guess there is no leaving agent to help when you leave the country

Many thanks in advance for your help!

I can only help you with some questions, as last time when I left I had my company do most items on your list.

Tax
Since I have only been here less than a year and always get taxed at source, should I still do my tax return?

Yes, if you want some taxes back.

Visa
I only have the L permit, how many days I can stay legally after my permit expires?

In principal none, I had to give my permit back and it was ok that I flew out 2 days later.

Bank accounts / Credit cards:
Credit card will be cancelled, bank accounts may be terminated, but depends on the bank, right?

It will take some processing time but to my knowledge there is no specific time frame.

Bills and Utilities:
Cancel all the utilities and bills, not sure how much notice I will need to give? Like 1 month?

Just tell them when you will leave your appartment. Make sure that you together with the landlord or janitor write down what f.e. the electricity usage was etc and file that through the internet with the provider. Simplest way to do that.

De-registration:
Does this mean I will need to de-register at the local stadt office (Yes, you need to go to the local council and deregister.

You should give written notice to your utility providers, as soon as you know your leaving date, some need minimum notice others not so. It is in your own interest as otherwise the service will still be in place after you leave and you foot the bill.
Our "nebenkosten" were usually sorted out in July, but I guess that varies. Depends on the type of administration infrastructure your building has too, I suppose.
English was fine for our termination letters, but remember it must be by registered post to be valid.