LOS ANGELES » American Express is preparing to launch a customer loyalty program in the U.S. that will enable shoppers at select retailers rack up points that they can use toward future purchases at Macy’s, Exxon Mobil, AT&T and other participating companies.

The free program, set to debut in May, is dubbed Plenti and will also include Nationwide, Rite Aid, Direct Energy and Hulu, American Express said Wednesday.

US Loyalty, a unit of American Express, will operate the program. But Plenti is not exclusive to AmEx’s cardholders. Customers of the companies in the program can earn points regardless of whether they pay with cash or a debit or credit card from another card issuer.

American Express also will be rolling out a Plenti-branded credit card that will let users earn additional points.

"For every dollar you spend you’re going to get a point on the credit card, plus whatever you get from that merchant," said Abeer Bhatia, chief executive of US Loyalty.

Full details on the financial terms between American Express and its partner companies were not disclosed. But one way American Express can cash in is as the retailers hit certain sales benchmarks.

"Revenue is definitely one of the elements of the performance-based target the program delivers, so we share in the upside," Bhatia said.

AmEx has been looking for new sources of revenue as long-standing, exclusive deals with Costco and JetBlue come to an end. Last month, the card issuer announced it would increase the annual fee on some of its popular charge cards, while also noting it would be beefing up some of those cards’ benefits as well.

The Plenti venture isn’t new territory for American Express.

The New York company acquired a consumer loyalty business in 2011 that runs similar programs in Italy, Germany, Poland, India and Mexico. The programs boast more than 60 million active customers, American Express said.

In the U.S., many companies offer loyalty programs, which are aimed at keeping customers coming back by allowing them to earn points toward discounts or rewards. Sometimes those points can be used for discounts elsewhere, such as a partner gas station operator.

Plenti takes the same idea but applies it across a network of several companies with varying products and services, giving users more options on where to save money.

For example, a customer who signs up for Plenti can earn points paying for gas or other goods at participating Exxon- or Mobil-branded stations, then use them to knock off some of the cost of buying clothes at Macy’s. Nationwide customers can use the points toward paying certain auto and property insurance bills.

The points, which are good for at least two years, are all worth the same at the companies in the program, with every 1,000 points equaling at least $10 in savings.

How many points one can earn from purchases can vary at each company, however.

For instance, spending $80 at Macy’s will result in 100 points, while at AT&T, $1 spent to pay for wireless service translates into one Plenti point.

"The idea is you’re going to be able to earn points for every dollar that you spend on your wireless bill and you’ll be able to use those points at any of the partners in the coalition, including at the AT&T store," said David Christopher, AT&T’s chief marketing officer.

Plenti users can get more points from promotional offers, which the companies plan to roll out from time to time.

Not all items sold by the retailers are eligible for discounts under the program, including tobacco and lottery tickets at Exxon Mobil gas stations and prescription drugs at Rite Aid.