Employee Stock Purchase Plan (ESPP)
Also called: ESPP, share purchase plan, SAYE
An ESPP lets employees buy company shares at a discount, typically 15%, often with a lookback that applies the discount to the lower of the price at the start or end of the offering period. That combination produces a very high annualised return if you sell immediately, which is why participating and selling on day one is the standard advice — holding converts a compensation benefit into a concentrated equity bet.