Wise, the money transfer company listed in London and on Nasdaq, grew net revenue by 23% to $1.45 billion in the first half, but heavier spending held back profit growth.
Pre-tax profit rose 9% to $334.9 million in the six months to 30 September, as operating costs climbed 28% to $1.15 billion.
That cut the pre-tax margin to 23% from 26% a year earlier.
Wise has been spending on technology, customer service, marketing and compliance, including about $15 million in costs linked to its dual listing on Nasdaq in May.
Net income rose 6% to $249.2 million.
The company stuck to its full-year guidance, expecting net revenue growth of 17.5% to 20% at constant currency and a pre-tax margin around the top of its 20% to 25% range.
Active customers rose 21% to 16.2 million, and the amount they moved across borders grew 24% to $141 billion, led by the US and Asia Pacific.
The average fee on those transfers, known as the take rate, slipped to 0.50% from 0.52% as Wise passed efficiency gains on to customers through lower prices.
Card revenue grew 43% to $252 million, with spending on Wise cards up 33% to $27.2 billion.
Customer holdings rose 28% to $43.5 billion, including $11.4 billion held in its investment product.
Interest income on customer balances increased 16% to $463.6 million, despite lower yields.
Wise also said its Belgian subsidiary had agreed a settlement with the Brussels prosecutor's office over queries about its business, with no admission of wrongdoing.
The group is about halfway through a share buyback expected to exceed $500 million.
More banks are adopting Wise's payments technology, with recent deals including OakNorth, the digital bank for entrepreneurs, and Vivid, the European financial platform.
