Savings Deposit Program (SDP) Calculator: 10% Guaranteed — Beat the Market?
Example: Amount deposited into SDP (max $10,000): 10000 $ · Deployment length: 9 months · Alternative investment return (annualized): 10 %/yr
| SDP interest earned (guaranteed) | $775 |
| SDP balance at end of deployment | $10,775 |
| Alternative investment final balance | $10,775 |
| SDP advantage over alternative (guaranteed vs risky) | $0 |
| SDP annualized return (always 10%) | 10 |
Worked example
Depositing the full $10,000 into SDP during a 9-month deployment at 10% APR compounded monthly earns about $780 in guaranteed interest, for a final balance of $10,780. The stock market alternative at 10% annualized would earn approximately the same — but with full downside risk. The SDP beats any alternative with risk-adjusted certainty: a guaranteed 10% is equivalent to a taxable return of ~12–14% for a service member in the 22% bracket, since combat-zone pay (and the SDP interest) may qualify for tax exclusion.
Frequently asked questions
Who qualifies for the Savings Deposit Program?
Service members must be serving in a designated combat zone and receiving hostile-fire or imminent-danger pay for a full month. Reservists called to active duty for qualifying operations also qualify. The SDP account must be opened while deployed — you cannot open it retroactively after returning.
Is SDP interest taxable?
Interest earned while the account is open during a qualifying combat zone deployment may be excluded from federal income tax under the Combat Zone Tax Exclusion. Consult your base finance office or a military tax specialist to confirm eligibility for your specific deployment.
What happens to the SDP after deployment ends?
You may leave funds in the account for up to 90 days after returning from deployment, and the 10% rate continues to apply during that grace period. After 90 days, the balance is refunded and stops earning interest.
Can I withdraw from SDP during deployment?
Generally no — funds are locked during the deployment unless you have a financial hardship. Early withdrawal could disqualify you from the program for that tour. Plan to treat it as illiquid for the deployment window.