ToplineMilwaukee-based financial company Fiserv’s stock collapsed more than 40% after cutting its earnings outlook and disclosing a sharp slowdown in its payment business, deepening investor concern amid an ongoing lawsuit over alleged inflated growth claims tied to its Clover platform.CHONGQING, CHINA - APRIL 20: In this photo illustration, the logo of Fiserv, Inc. is displayed on a smartphone screen, with the company's stock market performance and candlestick chart visible in the background, highlighting ...