UnitedHealth Group has informed the U.S. Securities and Exchange Commission (SEC) about a social media statement by hedge fund manager Bill Ackman. The investor had publicly speculated that the healthcare company may have artificially inflated its profits.

Ackman, founder of Pershing Square Capital Management, wrote on the platform X on Tuesday: "If I were still short selling stocks, I would short UnitedHealth. The SEC should take a close look at the company." He suggested that the insurer's earnings might be inflated by systematically denying medically necessary treatments. Shortly thereafter, he deleted the post.

UnitedHealth categorically rejected the allegations. "The health insurance industry is subject to strict regulatory supervision and profit limitations," the company explained. "The notion that insurers with low to mid-single-digit margins can earn excessively shows a fundamental misunderstanding of the regulatory structure of the industry.

An insider confirmed that UnitedHealth had informed the SEC about Ackman's statements. The company's shares fell by 2.2 percent on Wednesday, reducing the market capitalization to around 490 billion dollars.

The controversy comes a few months after the murder of Brian Thompson, CEO of the UnitedHealth insurance division, in Manhattan. His death sparked a wave of criticism of health insurers on social media.

Ackman, known for market-shaking statements, already caused a stir in 2020 with a dramatic warning about the economic consequences of the Covid-19 pandemic. His fund made 2.6 billion dollars at that time with hedges against a market crash.

Public documents show that Pershing Square currently holds no short positions against individual companies or the overall market. Nevertheless, Ackman remains an influential player in the financial markets with his statements.