Payments processor Fiserv saw its stock plunge up to 47% on Wednesday after cutting its annual earnings guidance. The company now expects a 16% drop in adjusted earnings per share for the year. CEO Mike Lyons called the changes a critical reset for the company, driven by slowing growth in Argentina. Fiserv also announced a new strategic action plan and management team overhaul. Former COO Takis Georgakopoulos and ex-UHG executive Dhivya Suryadevara were named co-presidents, while new CFO Paul Todd was appointed. The company also made three acquisitions in the third quarter. Analysts expressed disappointment in the results, with investor sentiment already weak prior to the news.

Read more at Yahoo Finance: Fiserv stock plunges. New CEO launches an executive shakeup.