Tom Gayner acquired 694 Thousand Marsh & McLennan Cos. shares worth $143 Million. That's 1.42% of their equity portfolio (23rd largest holding). The first Marsh & McLennan Cos. trade was made in Q4 2007. Since then Tom Gayner bought shares sixteen more times and sold shares on five occasions. The stake costed the investor $49.5 Million, netting the investor a gain of 188% so far.