Magnetar Financial LLC 4

What Happened

• Magnetar Financial LLC (a 10% owner / investment adviser to several Magnetar funds) reported the expiration of multiple short derivative positions tied to CoreWeave Class A common stock. The expirations occurred on March 20, 2026 and total 1,600,000 option-equivalent shares. All contracts expired unexercised and for no value, so there was no cash exchange and no open option positions remaining from these contracts.

Key Details

• Transaction date: March 20, 2026. Transaction code: E (expiration of short derivative position).
• Total derivative positions expired: 1,600,000 shares (aggregate of the listed expirations). Reported dollar value: $0 (options expired worthless).
• Origin of the options: part of a collar entered into on August 27, 2025; both the call and put expired unexercised because the closing stock price on March 20, 2026 was between the strike prices (footnote F1).
• The derivative interests were held directly by various Magnetar funds (footnotes F10–F15 identify the specific funds). Magnetar Financial is the adviser to those funds (footnote F2); the filing includes standard disclaimers of beneficial ownership (footnote F4).
• Filing timeliness: reported with period of report 2026-03-20 and filed March 20, 2026 (no late filing indicated).

Context

• This was not a purchase or sale of CoreWeave common stock — it was the natural expiration of options in a collar. Expiration for no value simply ends the derivative contracts and does not by itself change the underlying stock holdings reported for the funds.
• Magnetar here is acting as an institutional investor/adviser to funds, not an individual executive. Such expirations are routine and do not necessarily signal a change in the funds’ view of the stock.