September 2026 · Interim Note
The Book Gained $118.81 Today. AMD Alone Was Worth More Than Half of It
The book closed at $33,437.56 today, up $118.81 from yesterday’s $33,318.75 — a small net gain built on top of a much larger split. AMD did more than half the work by itself, up $62.65 on a 2.49% move, followed by Intel (+$36.68), Vertiv (+$26.79), SpaceX (+$24.24) and Arm (+$21.22). Twenty-three of my 32 positions closed higher. The other nine, led by SanDisk at −$118.48, very nearly erased the gain on their own — SanDisk's drop alone was worth almost exactly as much as the entire day's net. None of it traced to anything company-specific, covered in full in today’s News piece: most of the market simply gave back Thursday's inflation-and-oil-driven selloff. No trades.
Where the $118.81 actually came from
Figure 1 · Dollar book impact by position, September 11
Six gainers add up to more than $190; SanDisk alone gives most of it back
The nine largest single-day dollar movers in the 32-position book, September 10 to September 11, 2026 close. Share counts × the change in each position's closing price, using my own share counts. Source: Massive Market Data.
This is close to the mirror image of Thursday, when eight of my nine largest movers fell together on one macro story and only Palo Alto Networks moved the other way. Today, most of that same cohort — AMD, Intel, Vertiv and Arm — rose together on no new company-specific news, while Palo Alto Networks again moved opposite the group, falling 2.32% after rising Thursday. Today’s Opinion piece goes further into which names actually reversed cleanly and which didn’t — SanDisk, notably, fell both days.
| Position | Close | Day | Book impact | vs. my cost |
|---|---|---|---|---|
| Advanced Micro Devices (AMD) | $516.13 | +2.49% | +$62.65 | +158.92% |
| Intel Corporation (INTC) | $102.94 | +2.61% | +$36.68 | +175.02% |
| Vertiv Holdings Co (VRT) | $257.06 | +3.60% | +$26.79 | −15.69% |
| Space Exploration Technologies (SPCX) | $151.21 | +2.04% | +$24.24 | +12.01% |
| Arm Holdings plc (ARM) | $264.79 | +4.17% | +$21.22 | +27.41% |
| SPDR S&P 500 ETF (SPY) | $764.29 | +0.85% | +$19.38 | +16.64% |
| Vanguard S&P 500 ETF (VOO) | $702.56 | +0.85% | +$17.73 | +20.94% |
| Alphabet Inc (GOOGL) | $338.50 | +1.77% | +$17.70 | +23.28% |
| Meta Platforms (META) | $648.03 | +0.57% | +$16.90 | +176.56% |
| Invesco QQQ Trust (QQQ) | $714.88 | +0.87% | +$12.38 | +28.05% |
| The Cheesecake Factory (CAKE) | $102.70 | +1.52% | +$12.32 | +126.21% |
| Estée Lauder Companies (EL) | $97.12 | +0.67% | +$11.70 | +40.51% |
| GraniteShares 2x Nebius (NBIL) | $24.52 | −2.93% | −$22.20 | +165.66% |
| Palo Alto Networks (PANW) | $330.65 | −2.32% | −$39.20 | +106.24% |
| Sandisk Corp (SNDK) | $1,633.35 | −3.50% | −$118.48 | +238.02% |
AMD, and what a 2.49% day actually means on this position
AMD is up 158.92% against my $199.34 average cost on 5 shares, so today's $62.65 gain is arithmetic on a position that has already more than doubled — not a new signal about the business. The same is true of Intel (+175.02% vs. cost) and SanDisk, whose 3.50% drop today still leaves it up 238.02% against my cost basis. The more relevant number is at the book level: SanDisk's single-day loss was almost exactly as large as the day's entire net gain, which means one position is currently capable of erasing what the other 31 did together. The table below sizes that dependency directly, using SanDisk's own real cost basis and today's real position value rather than a guessed number.
| If SanDisk (2 shares, $3,266.70 at today's close) moves… | Position value | Total book value | vs. today |
|---|---|---|---|
| Unchanged | $3,266.70 | $33,437.56 | — |
| Another SMH-sized move (+1.47%, today's semiconductor-index gain) | $3,314.72 | $33,485.58 | +$48.02 |
| Another same-size drop (−3.50%, today's own SanDisk decline repeated) | $3,152.06 | $33,322.92 | −$114.64 |
| Illustrative stress case (−10%) | $2,940.03 | $33,110.89 | −$326.67 |
Assumptions, stated plainly. The $3,266.70 position value is my own real figure at today's close, from my own 2-share count. The first two move-size scenarios reuse today's own real, dated instrument and position changes — the SMH semiconductor-index gain and SanDisk's own decline — as illustrative magnitudes only, not as a claim that either predicts what SanDisk does next. The 10% stress case is not sourced to any analyst estimate; it exists purely to show the dollar sensitivity at a round number. None of these are price forecasts.
No trades today
The Blackout Rule and Holding Period exist for exactly this kind of session too: a broad, macro-driven rebound across positions I've already underwritten is not new information about any individual business, any more than Thursday's decline was. Today's move was explained by the same macro unwind covered in today's News piece, not by anything specific to AMD, SanDisk or any other name in the book. I made no trades.