Argenx stock slides 5% on CEO handover plan — what investors watch next
New York, Jan 5, 2026, 15:30 EST — Regular session Shares of argenx fell about 5% on Monday after the immunology drugmaker said Chief Operating Officer Karen Massey will succeed co-founder Tim Van Hauwermeiren as CEO, with Van Hauwermeiren set to become board chairman pending a shareholder vote on May 6. The stock was down 5% at $797.94 in afternoon…