New Delhi, Oct. 29 -- Fiserv Inc. stock plummeted by more than 44% on Wednesday, setting the company on track for a record single-day decline, after the payments software firm reported third quarter results that fell significantly below Wall Street estimates and slashed its growth forecast for the second consecutive quarter.

The highly disappointing earnings report underscores the mounting pressure on the fintech's core payments and merchant division. This business has struggled to maintain its momentum in the face of fierce competition and a noticeable slowdown in consumer spending.

Fiserv has now drastically revised its expectations, anticipating annual revenue growth of 3.5% to 4%, a sharp drop from its previous forecast of 10%. Like...