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%

September 2026 · Interim Note

A Nearly Flat Day That Didn't Feel Like One: My Cybersecurity Sleeve Lost $294 While the Book Fell Just $19.82

September 2, 2026 · Not a full monthly letter — a short check-in between them

An empty library reading room with long wooden tables and afternoon light
Two very different stories cancelled each other out inside the same $19.82.

The book fell just $19.82 today — on paper, close to nothing. It didn’t feel that way while I was watching it. Palo Alto Networks alone cost me $168.05 after falling 9.28% on its Q4 earnings report: a real revenue and EPS beat, undone by a subscription-revenue and gross-profit miss, covered in full in today’s News piece. Four more of my positions in the same cybersecurity and software cluster fell with it — Datadog (−$43.83), ServiceNow (−$37.08), CrowdStrike (−$23.30) and Fortinet (−$21.93) — for a combined $294.19 in losses across five names with, at most, one earnings report between them. What kept the day from being a bad one was almost entirely elsewhere in the book: Meta (+$66.26), Micron (+$45.28), SanDisk (+$33.06), the leveraged Nebius ETF (+$27.90) and Talen Energy (+$24.90) more than offset it. No trades.

−$19.82Net book impact, September 2 close vs. September 1
−$294.19Combined loss across five cybersecurity/software positions
+$66.26Meta, the day's single largest gain
−$168.05Palo Alto Networks, the day's single largest drag

The two halves of the book, side by side

Figure 1 · Dollar impact by sleeve

A $294 loss in five cybersecurity names, nearly matched by gains spread across the rest of the book

−$294 Cyber/SaaS sleeve +$274 Rest of book −$20 Net, all 32 positions

Cyber/SaaS sleeve = Palo Alto Networks, Datadog, ServiceNow, CrowdStrike and Fortinet combined. Rest of book = the remaining 27 positions combined. Share counts × the change in each position’s closing price, September 1 to September 2, 2026. Source: Massive Market Data closes, applied to my own share counts.

This is close to the opposite of most days I’ve written about this month: usually one or two names explain most of the move. Today, one sleeve of the book — five names that sit together in the same cybersecurity-and-enterprise-software corner of the portfolio — did nearly all of the damage, while the other 27 positions, spread across chips, consumer, power and index exposure, absorbed almost all of it. Today’s Opinion piece goes into why that sleeve moved together even though only one of the five actually reported earnings.

Positions moving more than $20 · September 2, 2026 close
PositionCloseDayBook impactvs. my cost
Palo Alto Networks (PANW)$328.48−9.28%−$168.05+104.89%
Meta Platforms (META)$592.85+2.47%+$66.26+153.01%
Micron (MU)$956.08+2.43%+$45.28+193.43%
Datadog (DDOG)$209.23−6.53%−$43.83+75.43%
ServiceNow (NOW)$136.72−4.32%−$37.08+61.30%
Sandisk (SNDK)$1,553.40+1.08%+$33.06+221.48%
GraniteShares 2x Nebius (NBIL)$20.69+4.71%+$27.90+124.16%
Talen Energy (TLN)$302.03+2.83%+$24.90−3.99%
CrowdStrike (CRWD)$203.42−5.42%−$23.30+114.67%
Fortinet (FTNT)$154.54−4.52%−$21.93+83.32%

The position that made the day feel better than the number

Meta Platforms (META) daily close vs. SPY, indexed, last 44 trading sessions through September 2, 2026. Source: Massive Market Data.

Meta rose 2.47% to $592.85 and was the single largest dollar contributor in the book today, at +$66.26 on my 4.6301 shares. I found no dated, company-specific headline explaining the move in the sources I checked; it appears to have traded with the broader mega-cap and AI-infrastructure complex that also lifted Oracle (+3.13%) and Nvidia (+3.21%), both on my watchlist rather than in the book. The position is up 153.01% against my $234.32 average cost. I have made no changes to it, and today’s move doesn’t change that: the Holding Period exists so a single day doesn’t force a decision, whether the day is Palo Alto Networks’ kind or Meta’s.

No trades today

The Blackout Rule and Holding Period exist for exactly this kind of session. A sharp move concentrated in one part of the book — even a $294 one — is not new information about any individual company’s fundamentals until I’ve had time to actually read the earnings report in full, which I have not yet done for Palo Alto Networks beyond the sourced coverage cited in today’s News and Opinion pieces. I made no trades.

Sources cited in full on the linked News and Opinion articles. Prices via Massive Market Data; dollar impacts computed from my own share counts. This note is educational and reflects my personal views only. It is not investment advice.