Magnetar Financial LLC and affiliated reporting persons filed a Schedule 13G with the SEC on November 13, 2026, disclosing beneficial ownership of 450,000 Class A ordinary shares of Rainier Acquisition Corp as of September 30, 2026.

Key Highlights

  • Aggregate beneficial ownership: Each of the four reporting persons may be deemed to beneficially own 450,000 Class A ordinary shares, par value $0.0001 per share, of Rainier Acquisition Corp.
  • Percent of class: The 450,000 shares represent approximately 5.10% of total shares outstanding, based on approximately 8,825,000 shares outstanding as of the filing date.
  • No sole voting or dispositive power: All 450,000 shares are held with shared voting power and shared dispositive power; sole voting and sole dispositive power are each reported as 0.
  • Shares distributed across six funds: Holdings include 126,000 shares for Constellation Master Fund, 99,000 for Structured Credit Fund, 94,500 for Alpha Star Fund, 76,500 for Xing He Master Fund, 36,000 for Lake Credit Fund, and 18,000 for Waterfront Series A Fund.
  • Reporting persons: The filing covers Magnetar Financial LLC (investment adviser), Magnetar Capital Partners LP (sole member and parent holding company of Magnetar Financial), Supernova Management LLC (general partner of Magnetar Capital Partners), and David J. Snyderman (administrative manager of Supernova Management).
  • Triggering date: The event requiring this filing occurred on September 30, 2026.

Magnetar Financial's Reported Position in Rainier Acquisition Corp Class A Shares

According to the Schedule 13G filed November 13, 2026, Magnetar Financial LLC serves as investment adviser to seven funds collectively referred to as the Magnetar Funds, exercising voting and investment power over the shares held in those funds' accounts. The filing identifies Magnetar Capital Partners LP as the sole member and parent holding company of Magnetar Financial, Supernova Management LLC as the general partner of Magnetar Capital Partners, and David J. Snyderman as the administrative manager of Supernova Management. All four entities are listed as reporting persons, each attributed the same aggregate beneficial ownership figure.

The filing states that as of September 30, 2026, the 450,000 shares were distributed among six funds: Magnetar Constellation Master Fund, Ltd (126,000 shares), Magnetar Structured Credit Fund, LP (99,000 shares), Magnetar Alpha Star Fund LLC (94,500 shares), Magnetar Xing He Master Fund Ltd (76,500 shares), Magnetar Lake Credit Fund LLC (36,000 shares), and Magnetar Waterfront Series A LLC (18,000 shares). The securities at issue are Class A ordinary shares of Rainier Acquisition Corp, CUSIP G73591102, with a par value of $0.0001 per share.

The filing discloses that the percentage of class, approximately 5.10%, was calculated based on information provided by the issuer in Forms 8-K filed on August 28, 2026 and September 3, 2026, which indicated approximately 8,825,000 shares outstanding. The reporting persons certified that the shares "were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer."

What Was Disclosed

Magnetar Financial LLC and three affiliated entities disclosed shared beneficial ownership of 450,000 Class A ordinary shares of Rainier Acquisition Corp, representing approximately 5.10% of the class, as of September 30, 2026, through a Schedule 13G filed on November 13, 2026.