(Reuters) - American Express Co said on Monday it had terminated some employees of its global commercial services division for inappropriately pitching some products, with respect to tax benefits.

The company said the issue primarily involved Premium Wire, which enables businesses to send wire payments globally, and that it had hired a law firm to investigate its small business sales practices in the United States, including sales of Premium Wire.

The Wall Street Journal had earlier reported that some of the company's salespeople had pitched a strategy to business owners, relying on a shaky interpretation of how tax law treats rewards points.

"This misconduct should not have happened," the company said in a statement. "As a result of an internal investigation, we terminated employees and disciplined others, made product changes, adjusted our sales compensation plan, required additional training, and reinforced our permitted sales practices and policies."

AmEx said it was discontinuing the Premium Wire Service and was eliminating the Membership Rewards component for a working capital solution, which was created for one supplier and its buyers.

The services under investigation accounted for less than a quarter of 1% of AmEx's global revenue from 2018 through September 2021, it said.

(Reporting by Sohini Podder in Bengaluru; Editing by Anil D'Silva)