<prompt> Human: My employer has an ESPP which allows me to purchase stock at a 15 discount twice a year. I can contribute a maximum of 15 of my earnings towards it.An ESPP seems like a guaranteed 15 return if I sell the stock immediately upon vesting. If I can afford the 15 hit on my salary, is there any downside to maxing out contributions towards the ESPP since Id basically be getting it all back plus 15 when I sell the stock?  <response>: Im just gonna be the pedantic one and point out its actually a 17.6 return 10.85. Theres no reason not to take full advantage. 