Share your insights or perspective on the financial matter presented in the input.

How much percent of my salary should I use to invest in company stock?
You're talking about ESPP? For ESPP it makes sense to utilize the most the company allows, i.e.: in your case - 15% of the paycheck (if you can afford deferring that much, I assume you can). When the stocks are purchased, I would sell them immediately, not hold. This way you have ~10% premium as your income (pretty much guaranteed, unless the stock falls significantly on the very same day), and almost no exposure. This sums up to be a nice 1.5% yearly guaranteed bonus, on top of any other compensation. As to keeping the stocks, this depends on how much you believe in your company and expect the stocks to appreciate. Being employed and dependent on the company with your salary, I'd avoid investing in your company, as you're invested in it deeply as it is.