In a recent peer review I was asked if I was willing to allow company to “retain part of my salary.” The exact percentage was not revealed. They used the word “retain” although they pressed that this is not related to my performance. 

Some context about the company: It is a start up and I have joined as software engineer 9 months ago. Company has two sources of income, “Product A” (which I am part of) and a bunch of services provided in education sector, not too unrelated to the main product.

I was told that this is going to be the case for at least until December of 2019 owing to poor performance of the product in market. 

The company’s recent funding round was not successful and I’m starting to worry that if I do not agree I will probably be let go soon.

What details should I consider before agreeing for part of my salary to be “retained” by employer?