NEW YORK () – The co-managers of the best stock mutual fund of this decade work out of a small office in Los Angeles, rarely talk with the financial media and have never appeared as guests on CNBC looking to raise their profile. Instead, portfolio managers Todd Beiley, 47, and Jon Christensen, 55, lead a team of five analysts who evaluate all companies in the Russell 2000 small cap index each year for signs of a competitive advantage. The time-consuming process has helped the $5.2 billion Virtus KAR Small-Cap Growth fund outperform every other actively managed mutual fund during the 10 years that closely corresponded with longest bull market in history, according to Morningstar data. With less than a month left in the decade, which opened nine months after the equity market bottomed during the financial crisis, the fund has posted a total return of 441% through November, including reinvested dividends. That performance is 20 percentage points greater than any other actively managed U.S. equity mutual fund, the Morningstar data showed. The Russell 2000 gained approximately 190%, while the S&P 500 returned 281% during this decade. “We’re not necessarily looking for the fastest-growing companies or those positioned in the right sectors for a macro trend, but businesses that can maintain a competitive position for a long period of time,” Beiley said. He noted that many of the companies the fund holds have few if any analyst coverage on Wall Street. Despite the fund’s success, its greatest challenge now is staying relevant. Over the last decade, the proliferation of low-cost index-based investing and exchange-traded funds has made stockpickers a relic of a time before the 2008 financial crisis, when investors were willing to shell out high fees for active management. Lower-cost passive management now accounts for 45 percent of all assets in U.S.-based stock funds, nearly double the 25 percent invested in passive funds a decade ago, according to the Investment Company Institute. Many active managers are struggling to draw new clients. “Increasingly investors are looking at the fee a fund charges and making that a higher priority than the performance record,” said Todd Rosenbluth, head of ETF and mutual fund research at independent research firm CFRA. “There are more and cheaper options than ever before.” Beiley and Christensen’s fund began concentrating its portfolio several years ago in fewer companies to differentiate it from its benchmark index. That also increased its risk and potential rewards. Over half of its assets are invested in 10 stocks, a group that ranges from auto parts maker Fox Factory Holdings Corp to trucking company Old Dominion Freight Lines Inc to electronic signature service DocuSign Inc, which had its initial public offering in 2018. The fund adds an average of two to three new stocks a year to its holdings of roughly 30 companies, and Beiley and Christensen are happy to invest in seemingly “boring” industries like trucking and used car sales. Yet their performance is anything but dull: shares of Paycomm Software Inc, an online payroll provider, are up 126 percent since the start of the year, while shares of auto-salvage auction company Copart Inc are up nearly 85 percent. “Our objective is to buy small and let the investment appreciate over time,” Beiley said. The fund typically makes an initial purchase in a company when it has a market value between $1 billion and $4 billion. Beiley and Christensen did not know of their industry-topping performance until they were informed of it by , but said they have no plans to capitalize on it. The fund is closed to new investors and there are no plans to open a new one. Both managers work on other small and mid-cap core funds at Virtus, which also have returns in the top 10 percentiles of their peers, according to Morningstar. They will likely continue on the same path of looking for fundamental strengths at a time when the broad market is increasingly made up of passive investors, a trend they expect will have a greater impact on small-cap shares in the next decade. “We’re well aware of the passive trend, and frankly I can’t argue with it,” Beiley said. “If you’re charging a high fee and not providing a higher service, then it’s hard to justify.” Reporting by David Randall; Editing by Alden Bentley and Dan GreblerOur Standards:The Thomson Trust Principles.