Hedge Fund Citadel already held every stock in Leopold Aschenbrenner's book before buying it

When Citadel bought Leopold Aschenbrenner's stock book at the end of July, we said the individual stakes would be almost impossible to find inside Citadel's own quarterly report of thousands of lines. On Friday the new report landed, and it turns out you'll find them after all. Every stock Situational Awareness owned is in there. So is every stock it used to own. And the report is dated June 30, about a month before the block trade. Citadel was already holding all of these names before it agreed to take his book.

This is the kind of overlap I like digging into, because the easy reading of it misses the point. The easy reading is that Citadel loaded up on Aschenbrenner's picks. A 13F is a snapshot of the last day of the quarter, and June 30 falls before the sale. So the filing says something quieter, and to me more interesting: the firm that ended up buying his book was already the house in every one of his names.

Here is the whole cohort, the 19 stocks he owned outright and the 8 he had already sold, with what Citadel reported in each as of June 30.

Citadel Advisors 13F, period ending June 30, 2026, filed Aug. 14. An asterisk marks a stock Aschenbrenner had already exited. Option values are the market value of the underlying shares, not money at risk.

The share stakes at the top of the table are real money. Citadel reported $197 million of Bloom Energy (BE) common stock, $161 million of Nebius (NBIS), and $153 million of SanDisk (SNDK), all ordinary shares held outright. The rest of the money on the page sits in options, and that's where you have to slow down.

There is a wrinkle worth understanding first. This 13F is filed by Ken Griffin's hedge fund Citadel Advisors, and it folds in his market-making arm Citadel Securities. Where Aschenbrenner picks a few dozen stocks, a market maker stands in the middle of everyone else's trades and holds inventory on both sides. You'll see it right in the numbers. Of the 16,127 lines in this filing, about 7,600 are options, and Citadel routinely holds puts and calls on the very same company. SanDisk is the clearest case, with $11.7 billion of puts and $10.3 billion of calls on the one stock. That's a firm making a market in it, holding both sides at once. So when the table shows a big options number, read it as the size of the inventory Citadel was handling in that stock. The money truly at risk is a small slice of it, and the dollar figure on an option counts the shares underneath it, which is why these figures tower over the actual share stakes.

That inventory is also the reason the block trade worked. Aschenbrenner sold the bulk of his public book to Citadel in one trade at the end of July, shorts and all, to strip the leverage out of the fund. Handing a single firm your entire portfolio overnight goes a lot smoother if it's already running a two-way market in everything you own. Citadel did, and that's a big part of why a firm its size could take the whole thing in a day.

The part everyone actually wants to know is the one thing this filing saves for later: whether Citadel held on to any of it or passed it straight back out. The block cleared after June 30, so it belongs to the next quarter. That answer lives in the following 13F, the one covering September 30, due in mid-November. For now, here's the certain part. When Aschenbrenner's book came its way, Citadel was already standing in every single name.

If you want to watch the same book unwind from the other side, we're tracking every Situational Awareness filing on the fund's page, including the Core Scientific (CORZ) block trades that dropped Aschenbrenner below the disclosure line in August.