Citi Names Top Life Science Tools & Diagnostics Stocks for Second Half

Citi says investor appetite is slowly returning to Life Science Tools & Diagnostics as AI disruption worries ease and sentiment on AI for tools turns positive, potentially supporting drug development and R&D reinvestment. For 2H 2026, Citi names WAT, WST, GH, and CRL as top picks: WAT is supported by base-business strength and the instrument replacement cycle, while WST remains constructive on GLP access and non-GLP traction despite a May cyber-attack that may drive one-time elevated expenses. Citi adds CRL to its upside 90-day Catalyst Watch, expecting DSA bookings and proposals to remain strong with book-to-bill above 1x and visibility into margin expansion.

Analysis

The cleanest takeaway is not that the group is “back,” but that the market may be underpricing operating leverage in the parts of life science tools most tied to replacement cycles and installed-base pull-through. That favors WAT first: once ordering confidence turns, instrument demand tends to inflect faster than broader lab spend, and gross margin can expand disproportionately because service/reagent mix lags the order upturn by a quarter or two.

WST looks more like a quality compounder than a cyclical snapback. The setup is less about near-term beat/raise and more about sustained pricing power from constrained capacity and compliance-driven demand; the market tends to give too little credit to regulatory complexity when it believes growth is “normalizing.” The one-sided risk is that biotech funding recovery is still fragile, so if venture/IPO markets stall, the expected second-half inflection can slip into 2027 and multiple expansion will fade quickly.

For CRL, the important second-order effect is that AI is more likely to improve biotech decision-making and funding efficiency than to eliminate outsourced R&D spend in the next 6-12 months. That should help proposal flow and booking visibility before it shows up in revenue. The contrarian miss is that if AI lowers the cost of iterating candidates, CRO demand can actually become more elastic upward, not less; the risk is only if biotech capital formation re-weakens, which would hit the whole subsector before AI adoption does.

Key Decisions for Investors

• Favor a relative long WAT vs. broad life-sciences tools beta (TMO/DHR basket proxy) into the next 1-2 quarters; thesis breaks if WAT fails to show order acceleration or management calls out replacement-cycle slippage on the next print.
• Buy WST on pullbacks rather than chasing strength; the better entry is any 5-8% post-event retrace, with a 6-12 month horizon tied to mix/margin expansion. Falsify if GLP-related demand normalizes faster than expected or if full-year margin guidance is cut.
• Add CRL on 90-day catalyst watch only if book-to-bill stays >1x and biotech funding conditions remain constructive; this is a 3-6 month setup, not an immediate trade. Exit if proposal activity rolls over for two consecutive quarters.
• Avoid making a broad long in the sector on AI headlines alone; the immediate beneficiaries are not the most AI-exposed names, but the ones with install-base, replacement, and compliance-driven demand. Use any rally to pair into weaker quality peers with slower recurring revenue conversion.