Shares of Interactive Brokers Group (IBKR) tumbled 5.30% in after-hours trading on Wednesday, following two significant developments that appear to have shaken investor confidence in the online brokerage firm.

The most notable news came from a regulatory filing which revealed that Interactive Brokers' Founder and Chairman, Thomas Peterffy, had acquired a substantial 25.9% stake in conservative media outlet Newsmax. The stake, worth over $6.2 billion and held through Conyers Investments, makes Peterffy the second-largest shareholder of Newsmax. This unexpected move by the company's chairman into a politically oriented media investment may have raised concerns among investors about potential conflicts of interest or distractions from Interactive Brokers' core business.

Adding to the downward pressure, Citigroup analysts cut their price target for Interactive Brokers from $242 to $215. While the reasons for the downgrade were not immediately clear, such moves by major financial institutions often lead to short-term selling pressure as investors reassess their positions. The combination of these two factors likely contributed to the significant after-hours decline in IBKR's stock price.

In a separate announcement that failed to offset the negative sentiment, Interactive Brokers revealed updates to its IBKR Desktop trading platform. The enhancements include multi-monitor support, new screeners, and overnight trading capabilities for US stocks and ETFs. While these improvements may be welcomed by the platform's users, they were overshadowed by the day's more impactful news items.

As markets digest these developments, investors will be closely watching how Interactive Brokers addresses concerns about its chairman's large stake in a media company and whether the firm can maintain its focus on its core brokerage business amidst these distractions.