Mutual fund giant Fidelity in late July invested about $20M in Marathon Digital (NASDAQ:MARA) across four funds, summing to a 7.4% stake. The funds in question - Fidelity Extended Market Index Fund (MUTF:FSMAX), Fidelity Nasdaq Composite Index Fund (MUTF:FNCFX), Fidelity Total Market Index Fund (MUTF:FSKAX), and Fidelity Series Total Market Index Fund (MUTF:FCFMX) - have a combined $170B in assets. Marathon over the past year has proven to be a levered bet on bitcoin, up 660% vs. the crypto's 240% gain. Other fund giants Vanguard and BlackRock also have stakes in Marathon, but of more modest size. "We’re super excited about the institutional ownership," Marathon CEO Fred Thiel tells Forbes. "If you look at the change from last year to this year and even the last two quarters have just been amazing [in] how much institutional ownership has grown in our stock." Marathon today is up 6.8% alongside a modest rally for bitcoin.