NEW YORK, Sept. 23 -- Three months into Takis Georgakopoulos's tenure running Fiserv, the company's market capitalization has not stopped falling. On Monday, the stock shed 4.3 percent to $47.19, extending a decline that began long before the new chief executive took his seat in June and has accelerated in ways that no longer look like a well-run payment processor adjusting to a new interest-rate regime.

The Federal Reserve's decision last week to raise its benchmark rate to a 3.75-to-4 percent target range added the most immediate layer of pressure on Monday. Payment processors and financial-technology platforms do not carry rate-sensitive balance sheets the way banks do. But their equity multiples expand and contract sharply with the r...