Cathie Wood's investment management firm ARK Invest bought nearly $2.2 million worth of Coinbase (COIN) shares in its first purchase of stock in the crypto exchange since Sept. 11.

ARK added 12,994 COIN shares to its Fintech Innovation ETF (ARKF) on Tuesday. COIN closed the day 0.73% lower at $167.69. ARKF now contains around $67 million worth of COIN stock, a 7.43% weighting of the fund's total value.

COIN has risen around 6.5% since ARK last purchased shares, but remains 20% lower since late August. It is possible that ARK is gearing up for a rally on the back of a surge in BTC's price, as tends to happen in October.

ARK also offloaded 135,665 shares of Robinhood (HOOD), worth nearly $3.5 million, to comply with a Securities and Exchange Commission (SEC) rule that forbids funds from having more than 5% exposure to securities in companies that themselves derive more than 15% of their income from the sale of securities. HOOD shares rose nearly 10% on Tuesday to close at $25.61.

Read More: Coinbase to Delist Unauthorized Stablecoins in EU by December