Three of the largest asset managers are diversifying their funds to hold blockchain stocks, throwing more establishment financial might behind bitcoin’s technology.

Charles Schwab has begun purchasing shares of Riot Blockchain, joining Fidelity and Vanguard – already investors in Riot, HIVE Blockchain Technologies, Hut 8 and BC Group – in allocating mutual fund holdings to a cryptocurrency company, according to financial filings with the U.S. Securities and Exchange Commission.

The stock purchases also double down on the mutual fund managers' equity investments and experiments in the space. Schwab this summer invested in Alchemy, an Ethereum application platform, while Vanguard has been piloting Symbiont's blockchain for foreign exchange transactions, and Fidelity has a digital assets arm – set to launch a trading service and a bitcoin index fund – and has backed Coin Metrics, Fireblocks and Everledger.

Filings for the first half of this year show Charles Schwab Investment Management, Inc. purchased 22,977 Riot shares for $52,000. Two Vanguard funds – the Vanguard Index Fund and Vanguard Valley Forge Index Fund – were invested in 954,229 Riot shares worth $2,118,000, and two Fidelity funds were separately invested in 176,242 Riot shares worth $230,115 (split between a NASDAQ index and three market indices) and 2,769,759 HIVE shares worth $1,003,163.

Riot Blockchain, based in the U.S., and HIVE Blockchain Technologies, based in Canada, provide services for mining bitcoin, a process where new cryptocurrency is minted.

Outside the U.S., a third Fidelity fund – Fidelity International – first acquired this year 10,451,094 shares valued at $1.80 each of Hut 8, a Canadian bitcoin mining company, and 17 million shares priced at HK$6.50 (US$8.30) of BC Group, a Hong Kong-based digital asset platform, earlier filings indicate.

The Riot shares in the two Vanguard funds and a third Vanguard fund – the Vanguard Institutional Index Fund – are back up from the last three years, which ended with them holding a combined 269,610 shares for $7,912,000 in 2017, 187,049 shares for $282,000 in 2018 and 826,391 shares for $925,000 in 2019.

Holdings also ticked up again for the Fidelity fund invested in Riot – the Fidelity Concord Street Trust – which bought 188,277 shares for $1,185,607 ending in 2018 and 159,263 shares for $270,375 ending in 2019. They dipped for the Fidelity Securities Fund invested in HIVE, with 5,792,880 shares for $82,433,000 ending in 2017, 4,972,700 shares for $821,000 ending in 2018 and 2,784,259 shares for $367,980 ending in 2019.

The Blackstone Group’s Alternative Investment Funds were also holding Riot Blockchain stock last year, but stopped including it in their portfolios.

Also read: Fidelity’s Chief Strategist Starts Bitcoin Index Fund

(CORRECT: 00:40 UTC): Removes reference to Vanguard in last paragraph.