3 Things You Need to Know About Medicare Advantage's Open Enrollment Period

Medicare Advantage maintains an annual open enrollment window from Jan. 1 to Mar. 31 during which existing Medicare Advantage enrollees may make a single change: switch to another Medicare Advantage plan or drop Advantage and enroll in original Medicare with a Part D plan; changes generally take effect the first day of the month after the request and are locked in for the remainder of 2026. While primarily consumer-focused, this enrollment period can drive insurer member churn, alter plan-level premiums and provider network utilization, and should be monitored by payers and investors for potential impacts on insurer risk pools and medical-loss ratios.

Analysis

Market structure: The Jan 1–Mar 31 Medicare Advantage (MA) window disproportionately benefits large, scale players that can quickly reprice networks and formularies — think UNH, ELV, HUM and CVS (Aetna) — while regional/single-state MA plans (e.g., MOH exposure) face higher churn risk and weaker negotiating leverage. Because enrollees can only make one change and only if already in MA, gross churn is capped; expect incremental member movements measured in low-single-digit percentages by plan rather than mass market share shifts over weeks.

Risk assessment: Key tail risks are regulatory (CMS payment/formula changes or star-rating adjustments) and operational (network contracting failures or coding/audit reversals) that could move margins >100 bps and swing guidance at quarter-ends. Immediate signals to watch are weekly CMS bulletins and early February call-center metrics; membership disclosures and 1Q earnings (Mar–May cadence) are the medium-term catalysts; durable MA penetration trends play out over quarters/years.

Trade implications: Tactical overweight large-cap managed care (UNH, ELV) to capture sticky premium and scale benefits; underweight/hedge regional MA names (MOH, CNC) and small-cap insurers that lack diversified risk pools. Use concentrated option spreads to play asymmetric upside into April–May enrollment prints while limiting capital at risk given likely short-lived volatility spikes.

Contrarian angles: Consensus often overstates churn risk because only MA enrollees can act and only once — historical windows show reversion within 4–8 weeks. Mispricings: implied vol on large-cap MCOs tends to spike ~10–25% into enrollment and then collapse; that creates cheap calendar spreads and verticals. Watch for unintended downstream hits to hospitals and specialty drug makers if formulary shifts accelerate PBM/insurer bargaining.

Key Decisions for Investors

• Establish a 2–3% portfolio long split 50/50 between UnitedHealth (UNH) and Elevance Health (ELV) now to capture expected membership stability and pricing power; target +10–15% in 3–6 months, place a hard stop/trim at -6% or if March/April reported membership loss >1% versus company guidance.
• Initiate a 1% notional protective put-spread on Molina Healthcare (MOH): buy 3-month 25% OTM puts and sell 15% OTM puts (limit max loss) to express downside vs. large-cap MCOs; increase hedge if early-Feb enrollment proxies show MOH losing >1.5 ppt local market share.
• Deploy options income on large-cap MCOs: sell April/May 1–2 month call credit spreads (short 3–6% OTM / buy 8–10% OTM) on UNH or ELV to collect vol premium ahead of enrollment close, cap sizing to 0.5–1% portfolio risk given potential headline sensitivity.
• Rotate 1–2% exposure into PBM/retail plays (CVS, CI/Evernorth) that benefit from Part D retention and formulary leverage; add only after confirming March plan formulary/posting updates, and exit if CMS issues adverse Part D rule changes within 30 days.