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T1 Index · The Trillion Dollar Club · equal-weight · base 2025-12-30 = 100

The T1 Index

One rule: a company joins the day it first closes at a $1 trillion market cap, and never leaves. The T1 is the equal-weight index of that club — 12 members were already in by the 2025-12-30 base, 6 crossed during 2026. Each addition counts only from the day it joined the club, never backdated — so the index tracks what the club itself earned, not the run that got a stock into it.

118.55 base 2025-12-30 = 100 +18.6% since inception
Members18 (12 founding · 6 added 2026)
As ofOct 8, 2026
MethodEqual weight, reset on each $1T crossing, drift between
History · momentum Rising +1.5 pts recent

195 points · since 2025-12-30

Members

Company Status In since Market cap Weight Return since base In-club return
MU Micron 2026 addition May 26, 2026 $1.17T 5.5% +254.2% +15.6%
AMD AMD 2026 addition Sep 21, 2026 $1.01T 5.6% +188.2% +0.8%
000660.KS SK Hynix 2026 addition May 6, 2026 $1.25T 5.1% +177.3% +13.1%
005930.KS Samsung Electronics 2026 addition Feb 3, 2026 $1.71T 5.4% +134.9% +69.5%
TSM TSMC Founding 2025-12-30 $2.26T 5.7% +53.9% —
AAPL Apple Founding 2025-12-30 $4.50T 5.6% +25.0% —
NVDA Nvidia Founding 2025-12-30 $5.43T 5.6% +23.2% —
2222.SR Saudi Aramco Founding 2025-12-30 $1.67T 5.6% +13.6% —
GOOGL Alphabet Founding 2025-12-30 $4.55T 5.4% +11.2% —
AMZN Amazon Founding 2025-12-30 $2.81T 5.5% +9.3% —
LLY Eli Lilly Founding 2025-12-30 $965B 5.6% +8.8% —
META Meta Platforms Founding 2025-12-30 $1.52T 5.4% +8.5% —
MSFT Microsoft Founding 2025-12-30 $3.42T 5.8% +7.9% —
AVGO Broadcom Founding 2025-12-30 $2.12T 5.5% +3.5% —
BRK-B Berkshire Hathaway 2026 addition Feb 4, 2026 $1.01T 5.6% +1.5% +1.4%
WMT Walmart Founding 2025-12-30 $912B 5.7% -0.6% —
TSLA Tesla Founding 2025-12-30 $1.56T 5.5% -17.5% —
SPCX SpaceX 2026 addition Jun 12, 2026 $2.08T 5.9% — -0.2%

"Return since base" measures the move since 2025-12-30; for 2026 additions this includes the run before they joined the club (context only). "In-club return" is what the index actually counts — the move since the stock crossed $1T.

Methodology

Membership. A stock is a member from the first day it closes at or above $1,000,000,000,000 (one trillion USD) market cap, and membership is permanent — Eli Lilly and Walmart crossed earlier and trade below $1T today, but stay in the club. The index starts on the last trading day of 2025 (2025-12-30), so the 12 stocks already in the club then are the founding members; later crossers are added on their crossing date.

Weighting. Equal weight, reset to 1/N only on each $1T crossing — when a new member joins the club, every position is rebalanced back to equal weight; between crossings the basket is left to drift, so a name that runs carries a heavier weight until the club next changes. The reset funds the new member by trimming the others, so the level stays continuous — no cash is added, and the return needs no time-weighting adjustment. Returns are USD total return; the US members price from EODHD, the three internationals (Samsung, SK Hynix in KRW; Saudi Aramco SAR-pegged) from their home markets converted to USD at the daily rate.

Additions enter honestly. A 2026 addition joins at the prevailing index level on its crossing date and contributes only from that day forward — the index never backdates a stock's pre-membership run. That is why Samsung's +46% in-club return counts, not the larger move that carried it over $1T.

Index reading is a diary entry on our process. Closelooknet publishes research, not investment advice.

FAQ · from the current data · as of 2026-10-08

Quick answers

What is the T1 Index?

An equal-weight index of every stock that has ever closed at or above $1 trillion market cap. A company joins the day it first crosses $1T and never leaves — permanent membership, no removals.

How many companies are in the T1 Index and how is it weighted?

18 companies (12 founding members at the 2025-12-30 base, 6 added during 2026). Equal weight, reset to 1/N only when a new member joins by crossing $1T; the basket is left to drift between crossings.

How does a company join the T1 Index, and can it be removed?

A stock becomes a member the first day it closes at or above $1,000,000,000,000 (one trillion USD) market cap, and membership is permanent — a company that later falls back under $1T (for example Eli Lilly or Walmart) stays in the club. 2026 additions are counted only from their crossing date forward; the run before they joined is not backdated into the index.

What is the T1 Index level right now?

As of 2026-10-08, the T1 Index closed at 118.55 (base 2025-12-30 = 100), +18.6% since inception.