GSK Stock Rises Almost 22% in 6 Months: Time to Buy, Sell or Hold?

GSK's stock has risen 21.5% in the past six months, driven by strong growth in its Specialty Medicines unit (up 19% in 2024 and 17% in Q1 2025) and regulatory successes, despite headwinds from slowing vaccine sales and generic competition. The company's forward P/E of 8.63 is below the industry average, and analysts' earnings estimates for 2025 and 2026 have increased, suggesting continued optimism, although the impact of the Inflation Reduction Act is expected to negatively impact sales by £400-500 million in 2025.

Analysis

GSK's stock has demonstrated significant strength, appreciating 21.5% over the past six months and outperforming its industry, sector, and the S&P 500. This performance is largely propelled by its Specialty Medicines unit, which saw sales increase by 19% in 2024 and 17% in Q1 2025, driven by robust demand for HIV and oncology drugs such as Nucala, Dovato, Cabenuva, Apretude, Jemperli, and Ojjaara. The company anticipates this segment will grow by a low double-digit percentage in 2025, even with a projected £400-500 million negative sales impact from the Inflation Reduction Act, and expects it to constitute over 50% of total revenue by 2031. GSK's pipeline is also a key positive, with recent U.S. approvals for its MenABCWY meningococcal vaccine, Blujepa for UTI, and Nucala for COPD, and five new product/line extensions anticipated in 2025. However, the Vaccines unit is facing headwinds, with Q1 2025 sales declining 6% due to lower demand for Arexvy (global sales down 57%) and Shingrix (U.S. sales down 21%), attributed to revised U.S. vaccination recommendations and challenges in reaching certain consumer segments. Despite these challenges and upcoming patent expirations for its dolutegravir HIV franchise (2028-2029), GSK's valuation remains attractive, trading at a forward P/E of 8.63, below the industry average of 15.63 and its own 5-year mean of 10.25. Furthermore, Zacks Consensus Estimates for earnings have risen for both 2025 (to $4.42 per share) and 2026 (to $4.82 per share), reflecting analyst optimism, and the resolution of most Zantac litigations has removed a significant overhang. GSK projects over 7% sales CAGR and over 11% core operating profit CAGR through 2026.

Key Decisions for Investors

• Investors currently holding GSK may consider maintaining their positions, given the strong growth trajectory of the Specialty Medicines unit, a robust product pipeline, and a positive long-term financial outlook which appears to offset near-term challenges in the Vaccines segment.
• Potential investors could view GSK as an attractive opportunity due to its valuation trading below industry peers and its historical average, coupled with upward revisions in earnings estimates and the recent resolution of significant litigation.
• All investors should closely monitor the commercial success of the five new product launches expected in 2025, the actual impact of the Inflation Reduction Act on sales, and any stabilization or recovery in the Vaccines unit, as these factors will be critical for sustained stock performance.