Market snapshot · September 18, 2026 close
S&P 500 (SPY) $761.69 −0.13% Nasdaq-100 (QQQ) $721.45 +0.60% Dow (DIA) $515.88 −0.48% Russell 2000 (IWM) $284.10 −0.52% 10-Year Treasury (IEF) $90.80 −0.49% Crude Oil (USO) $153.82 −0.93% Gold (GLD) $401.17 +0.74% US Dollar Index (UUP) $28.39 −0.02% Volatility (VXX) $17.76 +0.31% Semiconductors (SMH) $573.00 +2.17% Silver (SLV) $59.93 +1.65% Emerging Markets (EEM) $67.03 +0.19% Bitcoin (BTC) $81,055.00 +4.51% Ethereum (ETH) $2,630.20 +5.92% S&P 500 (SPY) $761.69 −0.13% Nasdaq-100 (QQQ) $721.45 +0.60% Dow (DIA) $515.88 −0.48% Russell 2000 (IWM) $284.10 −0.52% 10-Year Treasury (IEF) $90.80 −0.49% Crude Oil (USO) $153.82 −0.93% Gold (GLD) $401.17 +0.74% US Dollar Index (UUP) $28.39 −0.02% Volatility (VXX) $17.76 +0.31% Semiconductors (SMH) $573.00 +2.17% Silver (SLV) $59.93 +1.65% Emerging Markets (EEM) $67.03 +0.19% Bitcoin (BTC) $81,055.00 +4.51% Ethereum (ETH) $2,630.20 +5.92%
AEACapital Research

Independent student research — not an investment firm or financial advice

July 2026 · Interim Note

SpaceX Drops Below My Cost Basis, and I’m Still Not Selling

July 20, 2026 · Not a full monthly letter — a short check-in between them

Monday was quiet for the index — the S&P 500 barely moved, down 0.16% — but loud for two names I actually own.

SpaceX (SPCX), one of my Spec-bucket positions (8 shares, $135 average cost), fell 3.34% to $119.85 after a scrubbed Starship test flight caused by an engine ignition failure; Musk says a retry with replacement engines is days away. That puts the position roughly 11% underwater on a mark basis, which isn’t a fun number to look at. But a scrubbed test isn’t new information about the thesis I actually hold — reusable-rocket unit economics, Starlink’s recurring revenue, and the AI-datacenter option value in Starmind — it’s a mechanical delay to one specific milestone. Full story on the News page.

Tempus AI (TEM), also Spec bucket, fell 7.74% to $48.41 — just below my $49.73 cost basis — after a law firm announced it’s investigating Tempus’s own acquisition of Personalis for potential conflicts of interest. That’s a governance question about a deal Tempus is doing, not new information about the durability of Tempus’s core diagnostics business.

Elsewhere in the book, Nebius (NBIS) and my leveraged NBIL sleeve both moved up (+2.76% and +5.68%) despite a bearish Meta-competition headline making the rounds the same day, and SanDisk, Micron, and Intel all ticked higher.

No trades today

Neither the SpaceX nor the Tempus move breaks a thesis I’ve written up, and a single red print on a Spec-bucket position is exactly the kind of noise the Blackout Rule and Holding Period exist to keep me from reacting to.

Sources: cited in full on the linked News article. Price data via Massive Market Data. This note is educational and reflects my personal views only. It is not investment advice.