(Reuters) - Humana said the total members enrolled in its highly rated Medicare Advantage plans for people aged 65 years and above have reduced for 2025, sending the insurer's shares down about 12% in premarket trading.

The company said it has about 1.6 million, or 25% of its total members, currently enrolled in the plans rated 4 stars and above for 2025, down from 94% in 2024.

It said the star rating for a contract dipped to 3.5 from 4.5 in 2024. The contract accounts for about 45% of Humana's Medicare Advantage memberships.

The decline in star rating for 2025 will impact Humana's quality bonus payments in 2026, the company said.

Star rating details for 2025 are expected to be formally released by Centers for Medicare & Medicaid Services on or around October 10th.

(Reporting by Sriparna Roy in Bengaluru; Editing by Shinjini Ganguli)