Merck & Co., Inc.

Keytruda generated $31.7B in 2025 revenue and is approved for more than 40 cancer types. The problem is that its core patent protection expires in 2028, opening the door to biosimilar competition. The market has priced this risk aggressively: MRK trades at a forward P/E of roughly 12x, a 37-46% discount to large-cap pharmaceutical sector multiples, implying a severe post-2028 earnings decline is already baked into the stock.

The bull case is that the discount overestimates the damage. Merck's subcutaneous formulation (Keytruda Qlex) — converting a 30-minute IV infusion to a rapid injection — is designed to lock in patients with more convenient dosing, potentially delaying biosimilar substitution. Simultaneously, Winrevair for pulmonary arterial hypertension grew 88% in Q1 2026, and the oncology pipeline includes multiple Phase 3 programs with PDUFA readouts in 2026. Traders who believe pipeline execution outpaces the patent-cliff narrative find MRK's 12x multiple an attractive entry.

MRK is one of the most widely traded pharma pair trades on the street, most commonly against LLY. The pair captures the valuation divergence between Merck (trading at distress multiples due to pipeline uncertainty) and Eli Lilly (trading at premium multiples due to GLP-1 dominance). When sector rotation brings capital into value healthcare names, MRK tends to outperform LLY on a relative basis as mean-reversion buyers compress the valuation gap.

For income traders, MRK also offers a dividend yield above 3.5% at current prices — well above the S&P 500 average and competitive with investment-grade bonds. The combination of high yield, deep discount to sector, and near-term pipeline catalysts makes MRK a position that can generate returns from income, multiple expansion, or pipeline optionality — one of the more favorable risk/reward profiles in large-cap healthcare.