MD HB1450

Requires health insurance carriers to identify primary and secondary payors, determine amounts payable by each, and ensure combined payments do not exceed 100% of the total claim when coordination of benefits applies

Creates a new 9-month window for carriers to retroactively deny reimbursement when coordinating benefits with another private carrier, shorter than the existing 18-month period for Medicare/Medicaid coordination

Maintains the 18-month retroactive denial period only for coordination with Maryland Medical Assistance Program or Medicare, and the 6-month period for all other retroactive denials

Requires carriers to submit annual reports to the Insurance Commissioner on their coordination of benefits activities

Effective date: October 1, 2026