American Express Co., the biggest credit-card issuer by customer spending, said first-quarter profit increased 33 percent as consumer purchases climbed.

Net income was $1.18 billion, or 97 cents a share, compared with $885 million, or 73 cents, a year earlier, AmEx said.

“Record earnings this quarter reflect credit quality and billed business trends that are among the best we’ve seen,” CEO Kenneth I. Chenault, 59, said.

AmEx hasn’t offered debit cards, the most-used payment method. Instead, Chenault is expanding AmEx’s reach beyond affluent credit-card clients with a new payment system for smartphones and computers.

The electronic wallet, called Serve, may draw more transactions to AmEx’s global network, the fourth-biggest after Visa Inc., MasterCard Inc. and China UnionPay Co.