(Bloomberg) -- Cathie Wood snapped up more shares of Block Inc. and Coinbase Global Inc. as turmoil engulfed both companies Thursday.

The daily trading report from Wood’s firm ARK Investment Management showed that three of its exchange-traded funds bought about 338,000 shares of Block in the session, during which the payments firm plunged 15% after becoming the target of activist short seller Hindenburg Research. 

At the same time, two of the funds added a combined 269,000 shares of Coinbase, which slumped 14% after disclosing it faces potential regulatory action from the Securities and Exchange Commission. Both companies are among Wood’s top holdings.

Wood and ARK are well known for their high conviction bets, and frequently pounce on pullbacks in their top picks to increase holdings. The firm’s daily trading isn’t exhaustive — it excludes redemption activity — but it does represent the decisions taken by ARK’s portfolio managers.

Block shares tumbled after the report by Hindenberg, whose high-profile attack on Adani Group at one point wiped more than $150 billion off the Indian conglomerate’s market value. The short seller said it was betting against the Jack Dorsey-led firm, alleging that Block facilitates fraud. While analysts said many of the report’s claims were previously known and Block vowed to fight back, its Sydney-listed stock also dropped 18% on Friday.

Meanwhile, digital-asset exchange operator Coinbase disclosed this week it received a warning notice from the SEC about potential violations of securities law. Known as a Wells notice, it often — though not always — leads to enforcement actions.

Both stocks were down in premarket trading on Friday, signaling further declines.

The ARK purchases of Block — by the ARK Innovation ETF (ticker ARKK), the ARK Next Generation Internet ETF (ARKW) and the ARK Fintech Innovation ETF (ARKF) — were worth about $21 million based on closing prices. The Coinbase additions by ARKK and ARKW were worth almost $18 million.

All three ARK funds finished lower on Thursday. 

The bad week threatens to take the shine off what has been a better year than 2022 for Wood so far. Relentless monetary tightening has hammered ARK’s beloved speculative tech names, but as bets on further Federal Reserve interest rate hikes recede, the flagship ARKK fund has returned 21% in 2023 after plunging by a record 67% last year.

--With assistance from Aradhana Aravindan.

(Updates with extra context on Coinbase purchase throughout.)

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