Is Amex's OptBlue Working?: The OptBlue program was designed to improve consumer and merchant adoption of Amex cards by cutting fees for merchants. But do consumers care?

American Express' OptBlue program has added 700,000 small merchants in the past 14 months, wooed by the promise of better fees for Amex acceptance. But it's still too early to declare the program a success.

The next critical step is making sure Amex cardholders start using their cards at merchants that previously were reluctant to accept them, said Jeff Campbell, executive vice president and chief financial officer for American Express, during a second-quarter earnings presentation.

"It's a multi-year effort to change perceptions," Campbell said.

American Express introduced OptBlue in May of 2014 to enable its acquiring partners to negotiate pricing with small merchants that annually generate $1 million or less in Amex transactions. In the U.S., 14 major acquirers have signed on for the OptBlue program, and the New York-based card brand brought OptBlue to Canada three months earlier through Global Payments.

The program has generally been viewed as part of the "new" American Express, one seeking to shed its image as a card for the elite.

When American...