TSP C Fund: what's actually inside it
Officially the Common Stock Index Investment Fund. Large-capitalization US company stocks. Tracks the S&P 500.
504 holdings · expense ratio 0.048% · top 10 = 37.6% · concentration score 30.1/100 · holdings as of 2026-07-31
Top 25 holdings
| # | Holding | Weight | |
|---|---|---|---|
| 1 | NVDA | 7.55% | |
| 2 | AAPL | 7.05% | |
| 3 | MSFT | 5.36% | |
| 4 | AMZN | 4.13% | |
| 5 | GOOGL | 3.24% | |
| 6 | AVGO | 2.86% | |
| 7 | GOOG | 2.62% | |
| 8 | META | 1.90% | |
| 9 | JPM | 1.46% | |
| 10 | BRK-B | 1.46% | |
| 11 | MU | 1.44% | |
| 12 | LLY | 1.41% | |
| 13 | TSLA | 1.36% | |
| 14 | AMD | 1.21% | |
| 15 | XOM | 1.00% | |
| 16 | JNJ | 0.96% | |
| 17 | V | 0.93% | |
| 18 | WMT | 0.76% | |
| 19 | MA | 0.72% | |
| 20 | CSCO | 0.71% | |
| 21 | ABBV | 0.69% | |
| 22 | INTC | 0.66% | |
| 23 | COST | 0.66% | |
| 24 | BAC | 0.63% | |
| 25 | AMAT | 0.63% |
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 | 0.9% | 2.0 |
| TSP S Fund | 0.0% | 2.0 |
| TSP F Fund | 0.0% | 2.0 |
What has changed
We started recording TSP C Fund's headline figures in July 2026. There is only one month on record so far, so there is nothing to compare it against yet — check back next month.
Frequently asked
What does the TSP C Fund actually hold?
The C Fund — officially the Common Stock Index Investment Fund — tracks the S&P 500. The Thrift Savings Plan does not publish a holdings list and does not file SEC form N-PORT, so this page shows the 504 positions of VOO, which tracks the same index, as of 2026-07-31. The largest position is NVDA at 7.6%, and the top ten are 37.6% 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 C Fund itself. VOO tracks the same index, so its published holdings are the closest available picture of what the C Fund owns. Index funds tracking the same benchmark hold nearly identical portfolios, so the picture is close — but the weights are VOO's, not the TSP's, and the TSP has never published its own.
How much do the TSP funds overlap each other?
The C Fund overlaps the I Fund 0.9% by weight — I Fund 0.9%, S Fund 0.0%, F Fund 0.0%. 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 C 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 C Fund shown via VOO, holdings as of 2026-07-31. The TSP publishes no holdings of its own. Weights are fractions of the fund. Diagnostics, not advice.