Magnetar Financial LLC 4

What Happened
Magnetar Financial LLC, reported as a 10% owner through affiliated funds, recorded the expiration of multiple short derivative positions tied to CoreWeave Class A common stock on June 18, 2026. The filing shows paired call and put options (entered as part of a collar on Sept 30, 2025) expired unexercised, disposing of a total of 1,000,000 derivative units for $0 because the stock closed between the call and put strike prices. No shares were bought or sold; the options simply expired worthless.

Key Details

• Transaction date: June 18, 2026. Filing date: June 23, 2026 (appears 1 business day late vs. the 2-business-day Form 4 deadline).
• Aggregate expired quantity: 1,000,000 derivative positions disposed for $0 total proceeds.
• Transaction code: E — expiration of short derivative position. (Footnote F17 references expiration of a long derivative for no value under code K in other contexts.)
• Footnote F1: Options (call and put) were part of a collar entered 9/30/2025 and expired unexercised on 6/18/2026 because closing price fell between the strike prices.
• Holdings: The underlying positions are held across multiple Magnetar funds (see F10–F16). Magnetar Financial serves as adviser to those funds (F2); related entities disclaim beneficial ownership except as to pecuniary interest (F3–F4).
• Shares owned after transaction: Not specified in the excerpt; see the full Form 4 for post-transaction holdings.

Context
This was not a purchase or a sale of CoreWeave stock — the derivative contracts lapsed worthless, so no cash or shares changed hands. As Magnetar is reported as a 10% institutional owner via several funds and as adviser to those funds, this filing reflects institutional derivatives activity rather than insider executive trading.