Hedge fund billionaire Daniel Loeb has been in the news recently for targeting Sotheby’s CEO William Ruprecht, who has grown revenue steadily during his thirteen year tenure. However, according to an email published at The Gallerist, that’s not the only art company he has been pressuring recently. Loeb allegedly sent an email to a Gladstone Gallery employee Loeb allegedly sent an email to a Gladstone Gallery employee (whose name was withheld) explaining how he approaches business and, in particular, his approach to investigating companies. While he doesn’t actually make any threats, his list of anecdotes is noticeably devoid of happy…