TSP S Fund: what's actually inside it
Officially the Small Capitalization Stock Index Investment Fund. US companies outside the S&P 500: small and mid-cap. Tracks the Dow Jones U.S. Completion Total Stock Market index.
3,313 holdings · expense ratio 0.051% · top 10 = 11.4% · concentration score 0/100 · holdings as of 2026-09-30
Top 25 holdings
| # | Holding | Weight | |
|---|---|---|---|
| 1 | SPCX | 2.51% | |
| 2 | CASH | 2.31% | |
| 3 | SNOW | 1.42% | |
| 4 | NET | 1.35% | |
| 5 | NTRA | 0.72% | |
| 6 | MSTR | 0.67% | |
| 7 | ALAB | 0.67% | |
| 8 | LNG | 0.67% | |
| 9 | TWLO | 0.54% | |
| 10 | RVMD | 0.50% | |
| 11 | RKLB | 0.46% | |
| 12 | OKTA | 0.42% | |
| 13 | CRWV | 0.41% | |
| 14 | CRDO | 0.40% | |
| 15 | ALNY | 0.40% | |
| 16 | SUNB | 0.36% | |
| 17 | TEAM | 0.35% | |
| 18 | RBLX | 0.34% | |
| 19 | MDB | 0.34% | |
| 20 | FTI | 0.32% | |
| 21 | RPRX | 0.31% | |
| 22 | NVT | 0.31% | |
| 23 | ATI | 0.31% | |
| 24 | INSM | 0.30% | |
| 25 | LPLA | 0.29% |
Sector split
Overlap with the other TSP funds
The question a federal employee can actually act on: holding two of these, how much is the same underlying company?
| Paired with | Overlap | Effective Funds (50/50) |
|---|---|---|
| TSP I Fund | 4.2% | 2.0 |
| TSP F Fund | 2.3% | 2.0 |
| TSP C Fund | 0.1% | 2.0 |
What has changed
Between July 2026 and September 2026, from 3 months on record:
| July 2026 | September 2026 | Change | |
|---|---|---|---|
| Largest holding | CASH2.5% | SPCX2.5% | changed hands |
| Top 10 holdings | 8.8% | 11.4% | +2.6pp |
| Positions published | 3,307 | 3,313 | +6 |
TSP S Fund's largest position changed from CASH to SPCX over this window. The two weights are not compared, because they belong to different companies.
One point per month, taken from the issuer's published holdings file. Tracking began July 2026 — figures from before then were not retained.
Frequently asked
What does the TSP S Fund actually hold?
The S Fund — officially the Small Capitalization Stock Index Investment Fund — tracks the Dow Jones U.S. Completion Total Stock Market index. The Thrift Savings Plan does not publish a holdings list and does not file SEC form N-PORT, so this page shows the 3,313 positions of VXF, which tracks the same index, as of 2026-09-30. The largest position is SPCX at 2.5%, and the top ten are 11.4% of the fund.
Is this the TSP's real holdings data?
No, and that distinction matters. It is a labelled proxy: a different fund tracking the same index, not the S Fund itself. VXF tracks the US market excluding the S&P 500 — the same completion mandate — and is the closest covered equivalent. Index funds tracking the same benchmark hold nearly identical portfolios, so the picture is close — but the weights are VXF's, not the TSP's, and the TSP has never published its own.
How much do the TSP funds overlap each other?
The S Fund overlaps the I Fund 4.2% by weight — I Fund 4.2%, F Fund 2.3%, C Fund 0.1%. Overlap is the sum of the smaller weight in each fund over every holding both own, computed from the proxy holdings described above.
Why isn't the G Fund shown?
The G Fund — officially the Government Securities Investment Fund — is deliberately absent. It holds non-marketable US Treasury securities issued only to the TSP, which are not traded anywhere and have no market equivalent. Showing it through a bond fund would misrepresent an instrument whose defining feature is that its principal cannot fall.
Most federal employees hold more than the TSP
A TSP account is rarely the whole picture — there is often an IRA, a spouse's 401(k), or a brokerage account alongside it. Paste them all together to see the real overlap between your S Fund and everything else you own, and your own Effective Funds number. Free, no account, nothing stored.
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How it overlaps the other TSP funds
TSP S Fund shown via VXF, holdings as of 2026-09-30. The TSP publishes no holdings of its own. Weights are fractions of the fund. Diagnostics, not advice.