Is an Investment Portfolio Tracker Worth It for Active-Duty Military?

A mainstream investment portfolio tracker labels every TSP balance "TSP" and stops there. For an active-duty service member, that single line erases the choice between the G fund (Treasury yield, capital-preservation), the C fund (S&P 500), the S fund (US completion index), the I fund (developed-international), the F fund (US aggregate bonds), and the L lifecycle series. The Thrift Savings Plan crossed $1.006 trillion in assets across more than 7.2 million participants in mid-2025,^[] which makes it the largest defined-contribution plan in the country — and yet the tracker most service members reach for first treats it like a pension black box.

That's the central problem this page exists to solve. For roughly 1.34 million active-duty service members, a portfolio is rarely just "TSP plus brokerage." It's TSP at the fund level, an outside Roth IRA, a brokerage account, and — for anyone deploying to a combat zone — the Savings Deposit Program: a 10% APR cash vehicle administered by DFAS that sits entirely outside Plaid and every broker API.^[] A tracker that cannot see the SDP balance cannot see your real allocation.

What Service Members Actually Hold: TSP, IRA, SDP, and Brokerage

A typical active-duty portfolio in 2026 has four parts. The largest is TSP, with a 5% maximum Blended Retirement System contribution: 1% automatic plus a 4% match on the first 5% of basic pay, so a member contributing 5% receives a 5% match — 10% of basic pay going to TSP each pay period.^[] That match is the single best return in the portfolio and the easiest to leave on the table by under-contributing in any month of the year.

The second piece is a Roth IRA, which has its own $7,000 contribution cap for 2026 — separate from TSP's §402(g) elective-deferral limit and the §415(c) annual-additions cap.^[] An IRA contribution audit run on TSP balances alone misses this entirely.

The third is the Savings Deposit Program. SDP earns 10% APR on up to $10,000 deposited during a combat-zone deployment, and the 10% continues for 90 days after the member leaves the zone.^[] It's cash, but at a guaranteed real return that beats every TIPS yield on the curve. Treating it as "money in checking" understates the portfolio; treating it as a fund overstates it. Either way, a tracker has to make the call.

The fourth is whatever brokerage the member runs outside the TSP-and-IRA frame. For most service members that account stays small until they cross E-7 or O-3.

The Allocation Math: TSP G/F/C/S/I/L Funds Plus IRA and SDP

Inside the TSP, the five core funds split cleanly along risk: G is short-duration government securities, F is broad US bonds, C is large-cap US, S is small- and mid-cap US, and I is developed-international. The L (lifecycle) series automatically rebalances across those five toward a target retirement date. A target like "80% stocks / 20% bonds" maps to roughly 70% C-and-S, 10% I, and 20% G-and-F — but the exact split depends on whether the member treats the I fund as stocks (yes, by mandate) and the G fund as bonds or as cash-equivalent.

The calculation rendered below is what happens when an E-6 with eight years deploys for six months and maxes the SDP. Pre-deployment, the portfolio is $60,000 at 80/20. Post-deployment, once SDP unwinds and the $10,750 returns to checking, and the member's TSP and Roth IRA are six months further into their contribution schedule, the combined stock weight has drifted to roughly 69% — an 11-percentage-point gap from the 80% target. That drift is not a mistake; it is the mechanical consequence of holding cash through deployment. A tracker that doesn't see the SDP balance would record the stock weight as 80% and miss it entirely.

The Three Things to Track Monthly

For an active-duty portfolio, monthly review reduces to three checks:

1. Cross-account allocation drift. Compute stocks vs. bonds vs. cash on the combined TSP, IRA, brokerage, and SDP balance. Anything more than 5 percentage points off target is a rebalance trigger — not a panic, but a decision.
2. BRS match received vs. expected. A 5% match on December's basic pay only arrives if the member contributes at least 5% in December. Front-loading TSP contributions in the first eight months of the year is the most common reason a deployed member loses match dollars; the LES is the source of truth.^[]
3. CZTE annual-additions audit. During a combat-zone deployment, contributions can run against the §415(c) cap of $74,000 for 2026 instead of the $24,500 §402(g) elective-deferral cap.^[] Combat-zone earnings excluded from federal tax under IRS rules^[] still count toward §415(c). Track total annual additions (member plus employer) against the §415(c) ceiling, not the §402(g) one.

Where MFFT Fits In

MFFT supports manual TSP fund-level entry and a manual SDP balance line, which is what makes the cross-account allocation snapshot possible. Most consumer trackers can do neither. The drift calculation runs across all four account types together, not within a single account, so the SDP cash that returned from deployment shows up as cash in the combined view rather than disappearing into a checking-category bucket the allocation engine ignores. For deeper FIRE math specific to active-duty service members, the calculator covers BAH, BAS, CZTE TSP contributions, and the BRS pension as separate inputs.

What I'd Actually Track Each Month

On the first of every month, the four numbers I'd surface to a service member are: total portfolio value across TSP, Roth IRA, brokerage, and SDP; stock-weight drift versus target in percentage points; year-to-date BRS service match received versus expected; and year-to-date CZTE annual additions versus the §415(c) cap. For the quarterly cadence, add a Roth IRA contribution audit against the $7,000 cap and a TSP fund-mix snapshot against the lifecycle baseline.

That's not a dashboard. It's six numbers and one decision: rebalance, or don't.