NEW YORK (Reuters) – David Tepper’s Appaloosa Management and two of his funds received Federal Trade Commission clearance earlier this week that could clear the way for the billionaire to become an activist investor in drugmaker Allergan Plc.

Tepper received the Hart-Scott-Rodino anti-trust clearances on Wednesday, according to the FTC’s website.

Wells Fargo analyst David Maris said in a research note that Allergan “indicated this clearance provides flexibility to the filer as to whether they want take an activist approach to the investment or not.”

Tepper’s Appaloosa LP increased its stake in Allergan to 3.7 million shares from around 3.5 million shares over the last quarter, the firm said in a filing with the Securities and Exchange Commission on Tuesday.

“Allergan welcomes all investments in our company,” spokeswoman Amy Rose said, when asked about the clearances. Appaloosa was not immediately available for comment.

The company’s shares roe $5.70, or 3.7 percent, to $160.23 on Thursday.

Botox maker Allergan launched a strategic review of its business earlier this year. CEO Brent Saunders said in March the declining stock price required the company to look at all options “with a sense of urgency.”

Still, Saunders indicated on the company’s earnings conference call last month that he did not feel a fundamental change to the company’s strategy was necessary.

(Reporting by Michael Erman; Editing by Cynthia Osterman)