Boston Scientific (BSX) Stock Plunges 9% on Watchman Trial Concerns and Rating Cut

Key Takeaways

• BSX shares plunged 9% to $62.93, marking the lowest closing price since January 2024
• CHAMPION-AF trial data for Watchman FLX demonstrated non-inferiority to anticoagulants, yet revealed an elevated ischemic stroke incidence (3.2% versus 2%)
• Raymond James reduced its rating from Strong Buy to Outperform and lowered the price target from $97 to $88
• The rating adjustment reflected decelerating expansion in U.S. electrophysiology and Watchman segments, which contributed over 50% of year-over-year revenue growth
• Year-to-date, BSX has declined 34%, significantly underperforming the S&P 500’s 7.1% drop

Boston Scientific experienced a challenging trading session Monday, with shares tumbling 9% following a combination of underwhelming clinical trial results and an analyst rating reduction from Raymond James.

Boston Scientific Corporation, BSX

The CHAMPION-AF trial findings for the Watchman FLX left atrial appendage closure device were unveiled at a medical conference on March 30. From a technical standpoint, the outcomes appeared favorable. The device achieved non-inferiority when compared to contemporary oral anticoagulants such as Eliquis and Xarelto. Additionally, Watchman FLX users experienced reduced non-procedural bleeding complications, successfully meeting the trial’s primary safety endpoint.

However, market participants fixated on a specific metric. Trial participants receiving the Watchman device experienced a 3.2% rate of ischemic stroke events, contrasted with 2% among those taking oral anticoagulants. This differential, despite being relatively modest, triggered significant investor concern.

Importantly, this variance did not achieve statistical significance. Furthermore, stroke rate wasn’t designated as a primary study outcome. The research team intends to track participants for five years to obtain more comprehensive long-term stroke risk data.

Medical Experts Question Market Reaction

The trial’s co-principal investigator, Marty Leon, characterized the findings as “a very strong endorsement” for broadening the device’s clinical application. He articulated the risk-benefit calculation explicitly: an annualized 0.33% elevation in stroke or embolization events balanced against approximately 2.6% reduction in bleeding complications. Boston Scientific’s chief medical officer, Ken Stein, reinforced this perspective, emphasizing that stroke rates across both study arms were “incredibly low.”

Truist Securities observed that overall conference sentiment remained positive. Leerink Partners indicated that in-person reactions strengthened their confidence that trial outcomes would support increased Watchman procedure volumes moving forward.

Despite these professional assessments, investors remained unconvinced. BSX concluded trading at $62.93, representing its weakest close since January 30, 2024.

Concurrently, Raymond James revised its BSX rating from Strong Buy to Outperform while reducing its price objective from $97 to $88. The firm highlighted decelerating performance in two critical growth drivers: U.S. electrophysiology and Watchman, which collectively represented 26% of 2025 revenues and generated more than half of the company’s year-over-year expansion.

Raymond James Maintains Positive Outlook Despite Reduced Targets

Raymond James analyst Jayson Bedford emphasized that the rating change didn’t represent a fundamental reassessment. The firm continues to regard Boston Scientific as among the premier quality and fastest-expanding companies within large-cap medical device technology. The downgrade primarily reflected diminished short-term visibility rather than a shift in long-term investment thesis.

The firm reduced its 2026 and 2027 revenue projections by approximately 0.5% and 1.5% respectively. Updated models anticipate Watchman growth of 17% and 16% across the next two years, revised downward from previous estimates of 18% and 20%. Electrophysiology growth expectations were similarly adjusted to 15% and 14%.

Notwithstanding these revisions, Raymond James maintained that the valuation remains compelling. BSX currently trades at roughly 18 times anticipated 2027 earnings, compared to 21 times for comparable medical device peers.

Multiple other research firms — including Bernstein, Evercore ISI, Stifel, Truist, and Jefferies — maintain Buy or Outperform recommendations, with price targets spanning from $88 to $120.

BSX has declined 34% year-to-date. The stock reached a 52-week peak of $110 earlier this year.

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