Insurer Lemonade has warned that increased spending will negatively impact its near-term profit. This announcement comes amidst a report of an antitrust investigation into UnitedHealth Group Inc., which has caused its stock to fall more than 2% on Tuesday.

The Justice Department is reportedly examining the relationships between UnitedHealthcare and its Optum units. Investigators have interviewed industry representatives in sectors where UnitedHealth competes, including doctor groups, to inquire about certain relationships between the company’s UnitedHealthcare insurance unit and its Optum health-services division.

The investigation is focused on understanding how UnitedHealth’s acquisitions of doctor groups might impact competitors and consumers. The Justice Department’s actions indicate a heightened scrutiny of the health-insurance industry, with a particular focus on UnitedHealth’s market dominance and its potential effects on competition.

UnitedHealth, as the dominant U.S. health insurer in commercial markets with a 14% market share, and in Medicare Advantage with a 28% market share, has been a subject of regulatory attention. The company’s recent full-year 2023 revenues of $371.6 billion, with Optum accounting for over 60% of those sales, reflect its significant presence in the healthcare sector.

This is not the first time UnitedHealth has faced antitrust scrutiny. In 2022, the Justice Department sued to block its acquisition of Change Healthcare Inc., citing concerns about the potential misuse of competitively sensitive claims data. Despite the government’s challenge, the acquisition was ultimately approved by the court.

As a result of the recent developments, UnitedHealth’s stock has dropped 2.5% year-to-date, while the S&P 500 has gained 6.5%. The ongoing investigation and its potential implications continue to be a point of interest for investors and industry observers.