<prompt> Human: My wonderful fiancee 23 recently started a new job and has an option to buy company stock from her Fortune 100 company at a 15 discount. The stock has a holding period of 2 years. She feels very strongly that she should invest heavily in it as there has been a good historical return, even through the tumult around 2008. I, as a self proclaimed boglehead in training, feel that we cant project future gains from past performance. We both agree it is a great company that works in many sectors which may minimize the risk of catastrophic loss. We decided on 10 of her yearly investment 401k, IRA, and brokerage account contributions going to the company stock purchase plan. We have a good safety net and feel like this can be a good speculative portion of our portfolio. How much company stock is too much?  <response>: According to The Bogleheads-Guide To Investing,You should have no more than 10 of your portfolio in your own company. 