American Express(AXP) - Get Report  shares popped 4.7%, leading the blue-chip Dow Jones Industrial Average higher after first-quarter earnings showed the credit card company's strategic moves beginning to pay off.

The New York-based firm's earnings of $1.34 a share in the first three months of 2017 topped the $1.28 average estimate from analysts in a FactSet survey. Revenue of $7.9 billion, which also beat projections, was up 7% when the effects of the Costco (COST) - Get Report branded-card deal and currency-exchange losses were excluded.

"What surprised management was how strong revenue performance was in the month of March," Sanjay Sakhrani, an analyst with Keefe, Bruyette & Woods, said in a note to clients. "The company has to balance upside to results with maintaining the momentum seen as a result of the recent investments made, which will be a point of deliberation." 

CEO Kenneth Chenault has ramped up promotional spending and offered higher incentive rewards for cardholders in order to replace income lost with the Costco portfolio, but the moves also helped push overall expenses up 1% to $5.5 billion. That total was curbed by simultaneous efforts to take out $1 billion in costs.

"In many ways, our first-quarter results show the steady progress we are making on the range of growth and cost initiatives that we have put in place," CFO Jeffrey Campbell said on an earnings call. "These initiatives have been supported by the spending that we did over the last two years. We expect that these efforts will all come together to help us produce steady results during 2017."

Citigroup(C) - Get Report , one of the largest U.S. banks, won the rights to Costco's card after AmEx's agreement with the warehouse retailer collapsed in 2015. Citi processes the transactions through the Visa(V) - Get Report payments network.

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Net interest income -- which measures the profitability of a finance company's lending -- was $1.5 billion in the three months through March, a 5% decrease from a year earlier, , the company said in a statement.  The decline was duetoloweraverageloans,butincreased15%onanadjusted basis, in part because of higher rates, AmEx said.

Credit-card loans rose 11% to $62 billion after subtracting reserves against losses.

"The quarter looks strong and American Express seems to be on the right path to begin 2017 and hit the full year earnings-per-share target," Sakhrani said in a note to clients. 

Campbell said that any legislation to reduce corporate tax rates, as President Donald Trump has promised, would be a boon for the company, but AmEx isn't banking on that.

"Weareavery,verysignificanttaxpayer,soanyloweringofcorporateratesintheU.S.,weare likelytobeasignificantwinneronbecausewe'renotaparticularbeneficiaryofanyofthevaried andmanythingsthathelpotherorganizations,infact,paylowerrates," Campbell said. "We'renotrunningthecompanycountingonanychangesinthetaxarea,butitwould beagreatthingifitweretohappen."

KBW analysts maintained an outperform rating on the stock with a price target of $91. The company's shares rose to $79.08 in New York trading on Thursday, driving this year's gains to 6.8%.

This article, originally published at 5:29 p.m. on Wednesday, April 19, 2017, has been updated with company and analysts' comments.