August 2026 · Interim Note
Two Real Gains and One I Still Can’t Explain
SanDisk rose 13.67% Thursday, my biggest single-day move in this name since I started writing about it, and Netflix rose 5.43%. Both had real, dated reasons behind them. Datadog rose 4.70% the same day, and I don’t have one for that — which now makes four sizable, largely unexplained Datadog swings in six sessions since August 6.
What actually moved the book
SanDisk closed at $1,528.11 against my $483.21 average cost, on coverage arguing its recent 45% pullback from 2026 highs was an overreaction to sector rotation, not a change in the AI-driven memory-shortage thesis. Micron, my other memory-chip holding, rose 4.23% to $949.83 on the same argument. Netflix rose 5.43% to $78.24 after Bill Ackman’s Pershing Square disclosed a stake — a real, falsifiable fact, not a narrative — though it’s worth saying plainly that even after today’s jump, Netflix closed a hair below my $79.23 average cost. A strong day doesn’t erase a slow start. SpaceX fell 3.33% to $141.29 amid a skeptical piece on its cash burn and the coming August 21 share unlock, but that still leaves it above my $135.00 cost basis, having crossed back over it since Tuesday. Full sourcing on the News page; I go further on why I’m treating these three moves as different qualities of evidence, not just three green numbers, in today’s Opinion piece.
Away from the headline names, the book was broadly higher: 20 of 32 positions closed up on the day, against a S&P 500 that itself rose 0.70% and a Nasdaq-100 that rose 1.16%. The twelve names lower were mostly small moves — Cheesecake Factory’s 4.61% decline was the exception, and I have no dated news for that one either.
No trades today
The Blackout Rule and Holding Period exist for exactly this kind of session. A 13.67% single-day move in a name I own is not, by itself, a reason to trim; a fourth unexplained Datadog swing is not, by itself, a reason to buy or sell. Nothing today changed a thesis I’ve written up — it just moved prices around them.