Plenti doesn’t offer as much as you might think. It’s the name of a heavily promoted new loyalty program that offers rewards points for shopping at a variety of merchants. But Plenti is more complicated and more limited than its ads imply.

How it works: Plenti, which is overseen by American Express, allows you to earn points in a single account when you make certain purchases from 11 core businesses and hundreds of websites. The core businesses are AT&T…Alamo, Enterprise and National car rental…electricity provider Direct Energy…Exxon and Mobil gas stations…Hulu streaming video… Macy’s…Nationwide insurance…and Rite Aid. The online stores include HomeDepot.com, Sears.com, Staples.com, Travelocity.com and Overstock.com. You typically earn between one and five Plenti points per dollar spent with these businesses, and 1,000 points generally are worth $10 in savings on new purchases.

Catch: The list of limitations is long. Examples: Not all locations of participating merchants allow you to earn Plenti points…AT&T offers points for only “postpaid” cell-phone service, not home Internet or cable-TV service and not “prepaid” cell-phone service…Rite Aid gives points for only “select ­products” that change from time to time.

An even bigger catch: Only four businesses currently allow you to use Plenti points to purchase their products or services—Exxon, Mobil, Macy’s and Rite Aid. And there are limitations. Examples: Exxon and Mobil limit the number of points you can use at one time. Rite Aid does not allow you to use Plenti points to pay for prescriptions.

Originally published in the print edition as “An Unrewarding New Rewards Program.”