Pentair plc is facing a putative securities class action and a separate investor investigation after a series of 2026 disclosures tied to weakness in its Pool business wiped out value from the stock. A newly filed case, City of Warren General Retirement Health, Life and Disability Benefits Plan and Trust v. Pentair plc in the District of Minnesota, says investors who bought Pentair ordinary shares between March 11, 2025 and July 14, 2026 have until October 2, 2026 to seek appointment as lead plaintiff, broadening the period at issue beyond the previously reported Walters v. Pentair plc case in the Southern District of New York. The new complaint alleges Pentair and certain current and former executives misled investors about the impact of the company's 80/20 program, saying the initiative damaged longstanding commercial relationships, alienated customers, cost market share in the Pool segment, encouraged customers to buy inventory ahead of price increases and relied on above-normal rebates that boosted near-term sales at the expense of later periods. Those alleged issues later surfaced through a sequence of disclosures: Pentair's February 3, 2026 earnings update pointed to only 1% to 2% expected first-quarter 2026 net sales growth and flat Pool sales, while also announcing the departure of Chief Transformation Officer & Chief Supply Officer Steve Pilla and elimination of the chief transformation role; the stock fell more than 10%. On April 28, 2026, Pentair cut annual Pool net sales guidance to 1% to 3% growth and said channel partners needed to reduce purchases in the second and third quarters, after which the shares fell more than 12%. The sharpest move came after Pentair's July 14, 2026 preliminary second-quarter update, which said excess customer destocking cut Pool net sales by about $170 million, implying a roughly 40% year-over-year decline in the segment, drove total quarterly net sales down 17%, reduced full-year 2026 guidance from 2% to 4% growth to a 4% to 7% decline, and was accompanied by the abrupt departure of CFO Nicholas Brazis four months after he took the role. Pentair shares fell $11.35, or 15%, to $64.33 on July 15, 2026. Berger Montague has separately said it is investigating potential federal securities law claims.