Those funds dropped by an average of 42.1% last year, more than double the average 17% decline among U.S. stock funds, according to Morningstar.
The $6 billion Baron Partners Retail fund, which leads all US mutual funds with about 52% of its assets in Tesla shares, fell nearly 43% last year, while the $54 million Zevenbergen Genea Institutional fund, which has 13% of its assets in Tesla, fell nearly 59%.
Tesla fell about 65% last year, with declines accelerating after Musk decided to buy social media network Twitter, which some investors see as a distraction to the chief executive.
His net worth has fallen by more than $100 billion, according to Forbes, bumping him from the position of world's richest person.
The fund fell 67% last year, putting it near the bottom of all U.S. equity funds.