Utilize your financial knowledge, give your answer or opinion to the input question or subject . Answer format is not limited.

How can I get the most value from my employer's ESPP?
A 15% discount is a 17.6% return. (100/85 = 1.176). For a holding period that's an average 15.5 days, a half month. It would be silly to compound this over a year as the numbers are limited.  The safest way to do this is to sell the day you are permitted. In effect, you are betting, 12 times a year, that the stock won't drop 15% in 3 days. You can pull data going back decades, or as long as your company has been public, and run a spreadsheet to see how many times, if at all, the stock has seen this kind of volatility over 3 day periods. Even for volatile stocks, a 15% move is pretty large, you're likely to find your stock doing this less than once per year. It's also safest to not accumulate too many shares of your company for multiple reasons, having to do with risk spreading, diversification, etc.  2 additional points -  the Brexit just caused the S&P to drop 4% over the last 3 days trading. This was a major world event, but, on average we are down 4%. One would have to be very unlucky to have their stock drop 15% over the specific 3 days we are discussing.  The dollars at risk are minimal. Say you make $120K/yr. $10K/month. 15% of this is $1500 and you are buying $1765 worth of stock. The gains, on average are expected to be $265/mo. Doesn't seem like too much, but it's $3180 over a years' time. $3180 in profit for a maximum $1500 at risk at any month's cycle.