Groupon (NASDAQ GS: GRPN) is a deal-of-the-day website that features discounted gift certificates usable at local or national companies. Before going public in November 2011, GRPN amended its registration statement eight times. One SEC-mandated restatement forced it to change an auditor-sanctioned method of reporting revenue, reducing sales by more than 50 percent. Essentially, GRPN had initially counted the gross amount its members paid for coupons or certificates as revenue, without deducting the share (typically half or more) that it sends on to local merchants. The SEC also demanded GRPN remove from its offering document a non-GAAP metric it had invented called “adjusted consolidated segment operating income.” This measure was considered misleading because it ignored marketing expenses, which are one of the major risks of GRPN’s business model.