ABBV or MRK: Which Stock Should Investors Place Their Bet on in 2025?

AbbVie (ABBV) is positioned as the stronger investment over Merck (MRK) for 2025, having successfully navigated the Humira patent cliff with Skyrizi and Rinvoq driving significant revenue growth, projected to exceed $25 billion in 2025, and a robust pipeline supporting continued mid-single-digit revenue growth through 2029 due to no major patent expirations. Conversely, Merck faces challenges with a 48% decline in Gardasil sales and an over-reliance on Keytruda, whose patent expires in 2028, despite its pipeline expansion and cost-saving measures. This outlook, coupled with rising estimates and strong stock performance, positions AbbVie as the preferred choice despite its higher valuation.

Analysis

AbbVie has successfully navigated its Humira patent cliff, demonstrating a robust and diversified growth engine. Its successor immunology drugs, Skyrizi and Rinvoq, generated combined sales of $11.6 billion in the first half of 2025 and are projected to exceed $25 billion for the full year, underwriting a return to mid-single-digit revenue growth in 2025 and a high single-digit CAGR through 2029. This growth is supplemented by a 20.3% increase in its neuroscience portfolio and is supported by rising analyst estimates for 2025 (7.5% sales growth, 18.9% EPS growth). In stark contrast, Merck faces significant challenges despite the continued performance of its flagship drug, Keytruda, which grew 7% in H1 2025. The company's second-largest product, Gardasil, experienced a 48% sales collapse in H1 2025 due to weak demand in China and Japan, while other vaccine and diabetes franchises are also declining. This raises concerns about Merck's over-reliance on Keytruda ahead of its 2028 patent expiration. While Merck is cheaper, with a forward P/E of 8.88 versus AbbVie's 15.36, the market has priced in these diverging fundamentals, with AbbVie's stock up 20.3% year-to-date while Merck's has fallen 14.8%. AbbVie's primary risk is its high leverage, with a debt-to-capital ratio of 1.02, whereas Merck's core risk is its ability to diversify revenue before its key patent expires.

Key Decisions for Investors

• Given AbbVie's demonstrated growth execution and Merck's significant product-specific headwinds, investors may consider overweighting ABBV, as its premium valuation appears justified by a clearer growth outlook and positive earnings momentum.
• For long-oriented investors, AbbVie presents a compelling growth case with no major patent expirations this decade, but its high debt-to-capital ratio of 1.02 should be monitored as a key financial risk.
• A value-based position in Merck is a contrarian play that carries significant risk; it would be prudent to await evidence of a stabilization in Gardasil sales and material revenue from new products before considering an entry, given the looming 2028 Keytruda patent cliff.