AstraZeneca PLC (LSE:AZN) led the fallers on the main index, down 1.3% and echoing falls seen among US peers overnight.
It follows surprise news that federal payment rates to Medicare insurers next year will be lower than analysts predicted.
The Centers for Medicare and Medicaid Services said that 2025 payment rates will be in line with a proposal at the start of the year that the insurance industry had argued was too low.
Wall Street analysts had forecast the final rates would be some way higher than the proposal, the WSJ reported, as this was often the case in previous years.
Last night the biggest fallers on the S&P 500 included health insurance companies and other sector operators, from Humana Inc's (NYSE:HUM) 13% slide to 6% and 7% falls for CVS Health Corp (NYSE:CVS), Centene Corp (NYSE:CNC), UnitedHealth Group Inc (NYSE:UNH, ETR:UNH) and Molina Healthcare Inc (NYSE:MOH).