William Blair Investment Management 13F: New $199M Stake in POWI

William Blair Investment Management has taken a new position in Power Integrations, Inc. (NasdaqGS: POWI), according to a recent Form 13F filing with the SEC. The fund acquired 2,380,677 shares, valued at approximately $207.4 million as of the reporting period ending May 8, 2026.

What Changed in William Blair's Power Integrations Position

This acquisition marks a new position for William Blair Investment Management in Power Integrations. The fund bought 2,380,677 shares, which were not previously held, translating to a total value of about $207.4 million.

Other Institutional Activity in Power Integrations

Several other institutional investors also made moves in Power Integrations. BlackRock, Inc. added 10,445 shares, bringing its total to 8,521,749 shares worth approximately $436.3 million. Vanguard Portfolio Management LLC took a substantial position with 4,975,859 shares valued at about $254.8 million. Neuberger Berman Group LLC slightly reduced its holdings by 39,958 shares, resulting in a total of 3,933,099 shares valued at $201.4 million. Meanwhile, Wellington Management Group LLP increased its stake by 932,181 shares to a total of 3,356,153 shares, valued at $171.8 million.

Power Integrations, Inc. Stock Up 87.0%

Shares of Power Integrations, Inc. (NasdaqGS: POWI) are trading near $87.11. The company has a market capitalization of approximately $4.85 billion. Its P/E ratio stands at a hefty 290.37, with a forward P/E of 46.91, indicating expectations of future growth. The stock's 52-week range is $30.86 to $89.00, and it has a beta of 1.568, suggesting it is more volatile than the market. The company's 50-day moving average is $72.69, while the 200-day moving average is $49.93.

Recent Earnings

For its recent quarter, Power Integrations reported revenue of $446.3 million, reflecting a modest growth rate of 2.6%. The company's net margin was 3.72%, and return on equity stood at 2.36%. Earnings per share (EPS) were $0.30. The next earnings release is scheduled for August 6, 2026.

Insider Buying and Selling at Power Integrations, Inc.

Several insiders at Power Integrations have recently sold shares. On May 29, 2026, Sunil Gupta, Senior Vice President of Operations, sold 6,860 shares at an average price of $83.67. Balu Balakrishnan made multiple sales, including 124,287 shares on May 28 at $86.44 and 118,573 shares on May 26 at $81.72. Nicholas Brathwaite sold 1,728 shares on May 27 at $86.62, and 6,655 shares on May 26 at $82.71.

Analysts Set New Price Targets

Analysts have been active in updating their views on Power Integrations. On June 10, 2026, Needham initiated coverage with a 'buy' rating and a price target of $90. Susquehanna maintained its 'buy' rating on May 8, 2026, with a target of $85. Stifel also maintained a 'buy' rating on April 16, 2026, with a target of $62. The consensus among analysts is a 'buy' rating, with a mean target price of $73.60 based on opinions from five analysts.

About Power Integrations

Power Integrations, Inc. is a technology company based in San Jose, California. It specializes in designing and manufacturing analog and mixed-signal integrated circuits, which are crucial for high-voltage power conversion. The company serves a wide range of markets, including consumer electronics, industrial applications, and electric vehicles. With a focus on innovation, Power Integrations offers products that aid in efficient power management for devices ranging from smartphones to industrial motors. The company was founded in 1988 and is led by CEO Dr. Jennifer A. Lloyd.

Bottom Line

William Blair Investment Management's new position in Power Integrations reflects interest in the company's potential. Power Integrations is a notable player in the semiconductor industry, offering products for a broad array of applications. Investors often track 13F filings like this one to gauge institutional interest, though they represent past positions that may have changed since the filing date.