A prospective employer is asking for a copy of a pay stub from my current employer. Is it ethical for them to ask and for me to provide it to them? How can I politely say no to them? The prospective employer is a startup company. Appreciate your comments.

Thanks.

It appears they are trying to establish what you currently make. Do you not want them to know this info? If no, tell them that you do not have a stub.

You can politely say no to this prospective employer. What your previous pay stub states is not their business. While I would not be that blunt, I would decline their request saying I did not feel it pertained to employement with them.

I do not want them to know and I gave them a ballpark estimate on what I am expecting.

Yes. I agree with you - you have your monetary expectations with the company and can give them what you are looking for in the terms of salary.

Sounds like you might have fed them a line about your salary and now they are calling you on it.

In any case though, I think it is unethical for them to ask or for you to give a copy of your current pay stub.

They can either pay you want you need to join their company, or choose not to fill your need.

Of course they can merely call your past place of work and ask. It is one of the questions they ask when doing background checks.

I will assume you told them one figure, and they checked where you worked and it was not the same, and they merely want to verify you did not lie on the application.

You don't have to, but you will never get the job if you don't.
There is a reason they are asking for it,

So did you inflate your earnings on your applicaton??