A lookback is a provision in certain tax-qualified ESPPs. A lookback provision bases the purchase price not on the stock price at the time of purchase but, rather, on the price either at the beginning of the offering period or at the end of the purchase period, whichever is lower. With multiple purchase periods within a longer offering period (e.g. 12-month offering with two six-month purchase periods), the offering-date price stays the same while the purchase-date price changes.

That makes a lookback a good deal. It ensures a discount at purchase; and if the price has risen during the offering period, the discount from the market price on the purchase date will be even bigger.

Example: In your company's employee stock purchase plan:

  • Your company's stock price is $10 at the start of the offering and $12 at the end of the six-month purchase period.
  • You have a 15% discount on the purchase date that is based on the lower of either the price on that date or the price at the start of the offering.
  • You buy the stock at 15% off the $10, i.e. $8.50 (29% discount from the $12 market price on the purchase date).
  • If the stock price is $12 at the start and $10 at the end, your purchase price is also $8.50.
Stock price offering start $10
Stock price purchase date $12
Purchase price $8.50 (15% discount from lower of the two prices with lookback)

There are no rules about whether there must be a lookback (though it must be the same for every ESPP participant). With mandatory expensing, some companies are eliminating lookback provisions in their ESPPs (see a related FAQ).
