Fiserv's stock plummeted 44% Wednesday and headed for its worst day ever after the fintech company cut its earnings outlook and shook up some of its leadership team."Our current performance is not where we want it to be nor where our stakeholders expect it to be," wrote CEO Mike Lyons in a release.For the full year, Fiserv now expects adjusted earnings of $8.50 to$8.60 a share for the year, down from a previous forecast of $10.15 and$10.30. Revenues are expected to grow 3.5% to 4%, versus a prior estimate ...