Skype cofounder Jaan Tallinn gave $750,000 worth of cryptocurrency earlier this year to fast-growing AI company Faculty to address the risk of today’s AI systems — a gift worth even more with today’s surging prices. 

London-based Faculty, which develops machine learning systems for companies and governments, received 350 units of Ether, the coin associated with the Ethereum blockchain, in January 2018, worth $434,000 at the time, according to an interview with Tallinn in Fortune. He then gifted the company 50 Bitcoins in March this year, worth $316,000 at the time. 

The value of Ether has up 144% so far this year, and Bitcoin has gone up 300%, meaning Tallinn’s initial gift will now be worth millions of dollars. 

The Estonian investor said that he gave the money in crypto because he keeps most of his personal wealth in that form, and converting it into cash would have resulted in an unnecessary capital gains tax bill, reducing the amount he could give.

Tallinn had previously made seed investments in Faculty, and his company Metaplanet Holdings owns just under 9% of shares in the company. 

The money from Tallinn was given to help Faculty’s efforts to address the risks of AI systems, including things like algorithmic bias, lack of transparency, and data privacy concerns.

Faculty, which has been compared to US data analysis company Palantir, hit headlines in the UK in recent months after securing a contract to help the government forecast the availability of ventilators needed during the coronavirus pandemic. 

The contract was controversial because Faculty were awarded it outside of the bidding process normally used to secure government contracts. Under its previous name, ASI Data Science, Faculty helped the “Vote Leave” campaign during the Brexit referendum. 

Previously, Tallinn has put money into research looking at the more existential risks of AI. He gave money to the Future of Humanity Institute at Oxford University, which looks at the threats posed by superintelligent machines, and the Centre for the Study of Existential Risk at Cambridge University, which does similar work.

Tallinn said the work Faculty do looking at the bias of AI feeds into this much wider goal.

“Transparency and explainability are useful in current commercial settings, like, medical settings,” he told Fortune. “However, it also might make it much safer to deploy something that is smarter than us.” 

Tallinn initially became an investor using the money he made from selling his shares in Skype when it was bought by ebay in 2005. 

Faculty’s annual accounts show that it sold $144,000 of Ether between March 2019 and March 2020.

Freya Pratty covers news at Sifted. She has previously interned at Bloomberg and tweets from @FPratty