TSP F Fund: what's actually inside it
Officially the Fixed Income Index Investment Fund. US government, corporate and mortgage-backed bonds. Tracks the Bloomberg U.S. Aggregate Bond index.
1,856 holdings · expense ratio 0.048% · top 10 = 75.3% · concentration score 64.1/100 · holdings as of 2026-09-04
Top 25 holdings
| # | Holding | Weight | |
|---|---|---|---|
| 1 | AGENCY-MBS | 23.87% | |
| 2 | UST-3-10Y | 21.08% | |
| 3 | UST-0-3Y | 15.99% | |
| 4 | UST-10Y+ | 9.56% | |
| 5 | CASH | 2.84% | |
| 6 | 06051G | 0.50% | |
| 7 | 46647P | 0.50% | |
| 8 | 38141G | 0.34% | |
| 9 | 68389X | 0.33% | |
| 10 | 023135 | 0.32% | |
| 11 | 459058 | 0.31% | |
| 12 | 95000U | 0.29% | |
| 13 | 404280 | 0.28% | |
| 14 | 00206R | 0.27% | |
| 15 | 61747Y | 0.27% | |
| 16 | 92343V | 0.26% | |
| 17 | 172967 | 0.24% | |
| 18 | 91087B | 0.24% | |
| 19 | 30303M | 0.23% | |
| 20 | 91324P | 0.21% | |
| 21 | 00287Y | 0.20% | |
| 22 | 298785 | 0.19% | |
| 23 | 02079K | 0.19% | |
| 24 | 87264A | 0.19% | |
| 25 | 20030N | 0.19% |
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 S Fund | 2.5% | 2.0 |
| TSP I Fund | 2.5% | 2.0 |
| TSP C Fund | 0.0% | 2.0 |
What has changed
Between July 2026 and September 2026, from 3 months on record:
| July 2026 | September 2026 | Change | |
|---|---|---|---|
| Largest holding | AGENCY-MBS24.2% | AGENCY-MBS23.9% | −0.3pp |
| Top 10 holdings | 75.6% | 75.3% | −0.3pp |
| Positions published | 1,856 | 1,856 | no change |
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 F Fund actually hold?
The F Fund — officially the Fixed Income Index Investment Fund — tracks the Bloomberg U.S. Aggregate Bond index. The Thrift Savings Plan does not publish a holdings list and does not file SEC form N-PORT, so this page shows the 1,856 positions of AGG, which tracks the same index, as of 2026-09-04. The largest position is AGENCY-MBS at 23.9%, and the top ten are 75.3% 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 F Fund itself. AGG tracks the same index, so its published holdings are the closest available picture of what the F Fund owns. Index funds tracking the same benchmark hold nearly identical portfolios, so the picture is close — but the weights are AGG's, not the TSP's, and the TSP has never published its own.
How much do the TSP funds overlap each other?
The F Fund overlaps the S Fund 2.5% by weight — S Fund 2.5%, I Fund 2.5%, C 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 F 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 F Fund shown via AGG, holdings as of 2026-09-04. The TSP publishes no holdings of its own. Weights are fractions of the fund. Diagnostics, not advice.