Tom Gayner acquired 744 Thousand Marsh & McLennan Cos. shares worth $170 Million. That's 1.60% of their equity portfolio (20th largest holding). The first Marsh & McLennan Cos. trade was made in Q4 2007. Since then Tom Gayner bought shares twenty more times and sold shares on five occasions. The stake costed the investor $60.3 Million, netting the investor a gain of 182% so far.