These disclosures are from 13Ds filed with the Securities and Exchange Commission. 13Ds are filed within 10 days of an entity's attaining more than 5% in any class of a company's securities. Subsequent changes in holdings or intentions must be reported in amended filings. This material is from March 5 through March 11, 2026. Source: VerityData

Activist Filings

W.R. Berkley $(WRB)$ Mitsui Sumitomo Insurance raised its stake in the commercial insurance company to 58,780,450 shares. Mitsui Sumitomo Insurance did so through the purchase of 2,321,794 W.R. Berkley shares from Feb. 9 through March 3 at per share prices ranging from $68.53 to $73.42. The company purchased those shares pursuant to a Rule 10b5-1 plan entered into with Jefferies on Oct. 3, then terminated the plan on March 3. On March 5, Mitsui announced that the W.R. Berkley founding family will recommend Mitsui designee, Andrew Carrier, to join Berkley's board, with election expected at the June 2026 annual meeting. Following the latest purchases, Mitsui Sumitomo Insurance owns a 15.7% stake in W.R. Berkley's outstanding stock. Shares of W.R. Berkley have lost roughly 2.2% of their value in 2026.

Original Filings

Ziff Davis (ZD) Pale Fire Capital disclosed a new position in the digital media company of 2,597,799 shares. Pale Fire purchased 1,387,847 of those shares from Feb. 9 through March 2 at per share prices ranging from $25.12 to $31.50. Following the latest purchases, Pale Fire owns an initial 6.9% stake in Ziff Davis' outstanding stock. Shares of Ziff Davis have gained about 19.8% in value in 2026.

Increases in Holdings

Aurinia Pharmaceuticals $(AUPH)$ Tang Capital Management raised its stake in the biopharmaceutical company to 12,229,500 shares. Tang Capital did so through the purchase of 900,000 Aurinia shares from Feb. 27 through March 3 at per share prices ranging from $13.51 to $14.61. Following the latest purchases, Tang Capital owns a 9.2% stake in Aurinia Pharmaceuticals' outstanding stock. Shares of Aurinia Pharmaceuticals have lost roughly 3.5% of their value in 2026.

Decreases in Holdings

PBF Energy (PBF) Carlos Slim lowered his stake in the petroleum refiner to 26,469,098 shares. The Mexican billionaire sold 2,424,100 PBF Energy shares from Feb. 11 through March 4 at per share prices ranging from $34 to $45.10. Following the latest sales, Carlos Slim continues to own a 22.6% stake in PBF Energy's outstanding stock. Shares of PBF Energy have gained about 47.2% in value in 2026.

Mercury Systems $(MRCY)$ Jana Partners Management reduced its stake in the aerospace and defense contractor to 4,114,618 shares. Jana Partners did so through the sale of 852,057 Mercury shares from Feb. 9 through March 4 at per share prices ranging from $81 to $94.05. Following the latest sales, Jana Partners continues to own a 6.9% stake in Mercury Systems' outstanding stock. Shares of Mercury Systems have gained about 13.1% in value in 2026.

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March 13, 2026 20:29 ET (00:29 GMT)

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