A onetime portfolio manager for hedge fund firm Visium Asset Management LP was convicted of federal securities-fraud charges in the culmination of a three-year case that included the suicide of a fellow executive who was also charged. The jury deliberated for a little more than 90 minutes before finding Stefan Lumiere guilty on all three counts related to inflating the price of bonds in the firm’s credit fund to hide losses from investors. His conviction comes as the U.S. steps up efforts to police multitrillion-dollar bond markets, where securities are traded between parties and not over an exchange.