While institutional investors aren’t required to file their first-quarter Form 13F until May 15, Baillie Gifford has, in usual fashion, filed its form ahead of the deadline. A 13F is a quarterly filing that reveals the equity and option trades of an institutional investor.During the quarter, Baillie upped its stake in Rivian (NASDAQ:RIVN) stock by 714%, picking up 22.19 million shares compared to its Q4 ownership of 3.10 million shares. RIVN is now the firm’s 86th-largest position.On another note, Baillie c ...