Why BSX Stock Lost More Than Half Its Value While Sales Kept Rising

Boston Scientific (BSX) has fallen about 54% since late December 2025, and it now sits at $43.91, just above a 52-week low of $42.63. Device peers were mixed over the same nine months: Abbott lost about 17%, Medtronic barely moved, and Johnson & Johnson rose about 32%. The market repriced Boston Scientific's growth rate after management concentrated its guidance cut in two core product lines.

Boston Scientific Disappointed Twice, And Electrophysiology Was In Both

The first disappointment came on February 4, 2026, when the shares fell about 18% in a single session after the company disclosed disappointing U.S. electrophysiology sales. The second came in late July 2026, when Boston Scientific cut its full-year 2026 organic revenue guidance to 5% to 6%.

The cut was concentrated in two businesses. WATCHMAN is an implant designed for patients who cannot, choose not to, or should not take oral anticoagulation, and its U.S. market has slowed sharply.

About a third of U.S. WATCHMAN procedures are now performed concomitantly alongside other cardiac interventions, and those grew more than 60% in the second quarter of 2026.

The other two-thirds are stand-alone, and they fell in the low teens from a year earlier. U.S. WATCHMAN sales still grew 3% in the quarter. Management expects concomitant growth to slow materially in the second half against higher 2025 comparisons.

Management attributes the WATCHMAN slowdown to newly published clinical evidence on atrial fibrillation stroke risk, which it says altered doctor referral patterns. The chief medical officer points to fewer referrals for patients who simply prefer not to take a blood thinner.

Electrophysiology presents a complex challenge born of Boston Scientific's own early success: FARAPULSE converted the AFib market to pulsed field ablation faster than anticipated, leaving little unpenetrated ground as competitor devices enter the space.

In the U.S. that market is now about 80% PFA by revenue, which limits how much winning new users can offset the share rivals are taking. U.S. electrophysiology sales grew 3% in the second quarter of 2026, against 23% internationally.

But Three-Quarters Of The Company Is Still Growing

Management says the other business units, roughly 75% of revenue, should grow about 6% in the second half of 2026, in line with what they have delivered over many quarters. Total company organic sales grew 7% in the second quarter of 2026, at the top of the company's own guidance range.

Looking Beyond 2027

Management expects limited adjusted EPS growth in 2027, and says improving operating margins will be a challenge. A restructuring program targets about $500 million in run-rate savings exiting 2029, while trailing twelve-month revenue stands at roughly $21 billion.

For a company accustomed to delivering double-digit adjusted EPS growth, management's signal that 2027 is unlikely to match that pace explains why the market marked down the shares.

What is left to buy is 2028: seven product launches into a combined addressable market sized above $25 billion. Nearer term, the Penumbra acquisition is slated to close in the second half of 2026.

Until then the live question is whether stand-alone WATCHMAN procedures stop falling. Management has said it will not assume they recover until it sees them recover. That is the gap between knowing why the shares dropped and waiting for the underlying sales trends to stabilize.

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