In a notable first-quarter move, ADAR1 Capital Management LLC boosted its stake in Helix Acquisition Corp. II by 16.2%. The investment firm purchased an additional 65,591 shares, bringing its total holdings to 469,729 shares, according to a recent SEC filing.

The Swiss National Bank has pared back its investment in dental-equipment maker DENTSPLY SIRONA, selling 13,600 shares in the first quarter. The move cuts the central bank’s position by 3.4 percent to 385,100 shares—about 0.19 percent of the company, according to a newly filed SEC disclosure.