NEW YORK — Visa says its card transactions in the United States fell by 3 percent overall in April. And the payments-network company said in a regulatory filing Wednesday that the amount Americans rang up on their charge cards remained flat for most of May.

Visa Inc.'s stock fell more than 2 percent in Wednesday trading.

The company reported that it was especially hard hit on its debit-card transactions, which fell 12 percent in April, compared with an 8 percent gain in credit cards.

Visa makes money by processing card transactions for banks and other issuers. As the largest charge-cards payments processor in the world, Visa sees transaction volumes as an indicator of consumer-spending trends.

That might not be the case now, however, because Visa has dominated the market for debit-card transactions and is being especially affected by new federal regulations.

In October, the government limited the fees that banks can charge stores for card transactions, and some banks have eliminated rewards programs that encouraged customers to use debit cards.

Another regulation, effective, requires banks to give stores a choice of the network they use to process their payments.