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

September 2026 · month-to-date checkpoint

The rule is being tested while the thesis is working.

Through the September 10 close, the important change is not a new stock idea. It is that Sandisk appreciated back through the portfolio’s written 10% limit, while a broad risk-off session showed again how many different ticker symbols still move as one compute trade.

01 · The book

A difficult day was really a concentration test.

The portfolio lost $819.07 on September 10 after correcting a repeated $47 private-mark artifact. SNDK (−$143), MU (−$101), AMD (−$88), NBIL (−$85), and INTC (−$83) accounted for most of the damage. SPY fell 0.58%; the book fell 2.40%. That spread is consistent with a portfolio whose direct semiconductor exposure is 30.79% and whose broader AI-infrastructure, compute, software, and power theme is 59.79%.

30.79%

Direct semiconductors

59.79%

Broad compute theme

18.58%

Index ballast

2.27%

Leveraged sleeve

The five biggest positions are SNDK 10.16%, META 8.96%, AMD 7.56%, SPY 6.82%, and VOO 6.27%. Those are current weights, not target weights or rounded descriptions. The complete 32-position table is on Holdings.

02 · The breach

SNDK crossed 10%. The market did not make the decision for me.

The single-position limit is 10%. SNDK closed at $1,692.59 and 10.16% of the portfolio. It reached the breach through appreciation, not a new buy, but that distinction does not make the rule optional. I had already written that a trim was owed; I did not execute it. When the weight temporarily moved below 10%, price—not discipline—did the work.

Written ruleSingle position ≤ 10%September 10 resultSNDK 10.16% · breach

The Compliance Ledger now shows one breach, and the unchanged failure remains open in What I Got Wrong. This checkpoint records the condition; it does not invent a trade that has not happened.

03 · September data

Three releases are known. Two decisions are still ahead.

August payrolls

Nonfarm payrolls rose 162,000 and unemployment held at 4.1%.

BLS release →
August producer prices

Final-demand PPI rose 0.4% month over month; the 12-month increase was 5.4%.

BLS release →
August CPI

Not published as of this checkpoint. The latest available core CPI reading remains July’s 2.5% year over year.

BLS calendar →
FOMC meeting

The rate decision and new Summary of Economic Projections are still ahead.

Federal Reserve calendar →

Release facts above come directly from BLS and Federal Reserve pages accessed September 10, 2026. Scheduled information is labeled pending rather than described as an outcome.

04 · What comes next

Four checks, no invented certainty.

  1. SNDK: record whether the breach is resolved by an actual trim or merely another price move.
  2. CPI: add the August reading only after the September 11 release.
  3. FOMC: compare the September statement and projections with the July hold; do not pre-write a reaction.
  4. MU: update the earnings record after its confirmed September 29 fiscal Q4 report.

No positions were opened, closed, added to, or trimmed for this checkpoint. This is a September 10 snapshot, not the month-end letter.