Cathie Wood's ARK Investment Management purchased more than a million shares of Twitter Inc (TWTR.N) on the same day that Jack Dorsey resigned as the social networking site's chief executive.

According to the firm's daily trade report, following Tuesday's closing price of $43.94, ARK purchased 1.1 million Twitter shares for a total value of $48.9 million. They had fallen by 3.4 percent after starting the day lower.

On Monday, after the company named its technology chief Parag Agrawal as CEO, the stock fell by 2.7 percent, according to Nasdaq.

Ark also purchased 837,248 shares of online brokerage firm Robinhood Markets Inc (HOOD.O) on Tuesday, for a total purchase price of $21.7 million. It had purchased 915,063 shares the day before, taking advantage of a pullback in the price of the stock at the time.