William Blair Investment Management Trims IDEXX Laboratories Stake

Hedge fund reduces position in veterinary diagnostics company by 33%

Published on Mar. 2, 2026

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William Blair Investment Management LLC decreased its position in shares of IDEXX Laboratories, Inc. (NASDAQ:IDXX) by 33.0% in the third quarter, according to its most recent Form 13F filing with the Securities & Exchange Commission. The firm owned 459,019 shares of the company's stock after selling 226,069 shares during the quarter.

Why it matters

IDEXX Laboratories is a leading provider of diagnostic products and services for the animal health, water testing, and food safety markets. The company's stock has been a strong performer, but this filing indicates that at least one major institutional investor has reduced its stake, which could signal a shift in sentiment around the stock.

The details

According to the 13F filing, William Blair Investment Management's position in IDEXX Laboratories was reduced to 0.57% of its total investment portfolio, down from 0.85% in the prior quarter. The firm cited unspecified reasons for the reduction in its IDEXX holdings.

  • William Blair Investment Management filed its 13F report for the third quarter of 2026.

The players

William Blair Investment Management LLC

A Chicago-based investment management firm that oversees over $100 billion in assets.

IDEXX Laboratories, Inc.

A global developer, manufacturer and provider of diagnostic products and services primarily for the animal health, water testing and food safety markets, headquartered in Westbrook, Maine.

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The takeaway

This filing suggests that at least one major institutional investor has reduced its exposure to IDEXX Laboratories, which could foreshadow a broader shift in sentiment around the stock. However, the company's fundamentals remain strong, and it continues to be a leader in its markets.