Vitalik Buterin, the cofounder of Ethereum, deposited 600 ETH worth over $1 million to crypto exchange Coinbase on Monday, data from blockchain explorer Etherscan shows. 

The tokens were sent from the wallet address labelled “vitalik.eth,” which currently still holds 3,993 ETH worth $6.5 million at current prices.

Buterin’s transfer comes amid a week of volatility for ETH, which is down 10% over the last seven days. A sharp selloff late on Thursday last week saw crypto traders suffer $1 billion worth of liquidations, with ETH liquidations alone accounting for $302 million over 24 hours.

Before sending the 600 ETH to Coinbase, Buterin repaid 251,000 Rai Reflex Index (RAI) tokens on the Maker protocol and withdrew 1,000 ETH worth $1.67 million.

Although several market participants speculated that Buterin sent the ETH to the crypto exchange to sell, the reason behind the transfer remains unknown. Over the last few years, however, Buterin has sold ETH after similar transfers to crypto exchanges, along with other lesser known tokens that people have sent to his wallet. 

In fact, earlier this year, Buterin moved $3.6 million ETH to crypto exchanges Kraken, Gemini and Coinbase, according to data from Arkham. Incidentally, the timing of these transfers also coincided with a drop in ETH’s price.

On Sunday, another Ethereum wallet address which had acquired ETH during the Initial Coin Offering (ICO) in 2014, moved 191 ETH worth around $320,000 to another address after more than eight years of leaving it untouched.