Tom Gayner's position in Berkshire Hathaway is currently worth $683 Million. It makes up 7.02% of their stock portfolio and is their biggest holding. The first Berkshire Hathaway trade was made in Q4 2007. Since then Tom Gayner bought shares thirteen more times and sold shares on ten occasions. The stake costed the investor $171 Million, netting the investor a gain of 300% so far.