C Fund

U.S. large cap fund

Green check mark

Invested as of Jul 1, 2025


Price
$98.6743
(Jun 30, 2025)
10-month SMA
$92.8468
(Sep 30, 2024 - Jun 30, 2025)

S Fund

U.S. small/medium cap fund

Green check mark

Invested as of Jul 1, 2025


Price
$92.0521
(Jun 30, 2025)
10-month SMA
$88.6597
(Sep 30, 2024 - Jun 30, 2025)

I Fund

International stock fund

Green check mark

Invested as of Jul 1, 2025


Price
$49.7247
(Jun 30, 2025)
10-month SMA
$44.8048
(Sep 30, 2024 - Jun 30, 2025)

How it works

This is a TSP investment model based on Mebane Faber's paper, A Quantitative Approach to Tactical Asset Allocation. Faber describes an investment system that is based on comparing the current price of a fund to the 10-month simple moving average (SMA) of that fund, and making a buy/sell decision based on that comparison.

Applied to the TSP, this means we watch the C, S, and I funds. If the price of any of these funds drops below its 10-month SMA, we move money from that fund to the G fund. Conversely, if a fund's price rises above its 10-month SMA, we move money from the G fund to that stock fund. You decide how much of your investment you want to allocate to each fund. The F fund and the L funds are not a part of this model.

Faber's model only looks at the prices once a month after the final trading day of the month. This is a perfect fit for the TSP since we are only allowed two trades per month plus one move to the G Fund per month.

I originally learned of this model from a Federal News Radio article, which describes in detail how Faber's model can be applied to the TSP.

If you are considering following this model for your investments, there are a few things you should keep in mind: