Managers of the Netherlands-based Plethora Precious Metals Fund say that the “key to getting monster-sized returns in mining equities is to be small,” according to an article in Bloomberg.

Compared to fund giants like BlackRock and Vanguard, Plethora’s $20 million in assets is small, but the fund isn’t looking to get bigger. The article reports that the fund invests in young mining exploration companies, mostly in gold. Its founder, Peter Vermeulen, said in an interview, “We invest in small teams of geologists that are looking for ore deposits. Those companies are so small that it is practically impossible to allocate a lot of money there. However, their returns—when they have found gold—are huge.” Fund data shows that it has returned 502 percent over the last six years, stellar performance compared to the NYSE’s Gold BUGS Index, which suffered a 65% drop in the same period.

Plethora’s strategy is to hold a stake of between 5 percent and 15 percent in approximately 20 portfolio companies with a market valuation of $20 million or less. Fund manager Douwe van Hees explains that larger funds are not able to research and invest in smaller companies, but that Plethora is able to “allocate money very specifically” without having to invest in a “limited number of less performing assets.” He said that Plethora recently returned one million euros to investors, the second such occurrence in two years, and hasn’t taken any new money since 2016.