Three weeks ago, the most important data release of the first quarter occurred. On Feb. 14, while some people were shooting proverbial love arrows at their significant others, institutional money managers with at least $100 million in assets under management were filing Form 13F with the Securities and Exchange Commission. A 13F allows investors to see what Wall Street's smartest and most successful investors have been buying, selling, and holding. During 13F season, it's not uncommon for investors to focus their attention on the moves made by billionaire asset managers.