Pershing Square, the activist hedge fund led by Bill Ackman, disclosed an 8.5% stake in industrial conglomerate Rockwell Automation Inc. in a 13F filing on Wednesday. The position is valued at approximately $2.2 billion.

The disclosure fueled speculation about Pershing Square’s intentions. The fund has historically pushed for major strategic changes, including asset sales or full company acquisitions.

Pershing Square has not publicly commented on its plans for Rockwell. Rockwell shares rose more than 7% in after-hours trading following the disclosure.

Analysts are anticipating a potential proxy contest if Rockwell management is not receptive to Ackman’s likely proposals to unlock shareholder value.