TSP Loan Guide: Dangers of Borrowing from Your Thrift Savings Plan

Borrowing from your retirement account might seem like a convenient way to access cash; after all, you are paying yourself back with interest. But the true cost of a TSP loan is often much higher than the interest rate suggests, and understanding why is essential before making this decision.

The interest on a TSP loan is tied to the G-Fund interest rate, which resets monthly. As of May 2026, that rate is 4.500%, significantly higher than the near-zero rates seen in recent years. While paying yourself 4.500% interest sounds appealing, the real question is what that money would have earned had it stayed invested in your TSP, and that difference is almost always larger than it appears.

TSP Loan Basics: How They Work

A TSP loan is when you borrow money from your TSP account for personal use. Here are the fundamental details.

How Much Can You Borrow?

The loan amount can range from $1,000 to $50,000 but cannot exceed:

• Your contributions and earnings on those contributions

• The greater of $10,000 or 50% of your vested account balance minus any outstanding loan balance

• $50,000 minus your highest outstanding loan balance at any point within the past 12 months

Note: Money invested in the TSP Mutual Fund Window is not available for borrowing and is not included in these calculations.

Types of TSP Loans

A general purpose loan requires no documentation and must be repaid within 5 years. A residential loan requires supporting documentation verifying the proceeds will be used for the purchase or construction of a primary residence, and can be amortized over a 15-year period. For either type, payments must start within 60 days of the loan disbursement.

TSP Loan Interest Rate

Interest is calculated at the G-Fund rate for the month before the loan is processed. As of May 2026, this is 4.500%, though the rate resets monthly and should be verified at the time of any loan application. TSP loan payments are not tax-deductible. However, the interest paid goes back into your TSP account.

TSP Loan Fees

All loans require a $50 administrative fee taken directly from the loan proceeds. For example, a $10,000 TSP loan will result in net proceeds of $9,950, but the loan will still be for $10,000.

TSP Loan Eligibility Requirements

• Must be employed by the federal government or a member of the uniformed services

• Must be in pay status because repayments are set up as payroll deductions

• Can only have two loans outstanding at one time, either two general purpose loans or one general purpose loan and one residential loan

• Must have at least $1,000 of your own contributions and earnings in your TSP account — agency contributions and earnings cannot be borrowed

• Must not have repaid a TSP loan of the same type in full within the past 30 business days

• Must not have had a taxable distribution of a loan within the past 12 months unless it was the result of your separation from federal service

• Must not have a court order against your TSP account

Additional Requirements for Residential Loans

A residential loan can only be used to purchase or construct a primary residence, which may include a house, townhouse, condominium, shares in a cooperative housing corporation, boat, mobile home, or recreational vehicle.

A residential loan cannot be used for refinancing or prepaying an existing mortgage, construction of an addition to an existing residence, renovations to an existing residence, buying out another person’s share in your current residence, or the purchase of land only.

Why Would Someone Take a TSP Loan?

There are many reasons someone might take a TSP loan, but two stand out as the most common:

• The borrower needs the money

• The borrower believes there is a better use for the money than leaving it in TSP investments

Reason 1: The Borrower Needs the Money

This can be a legitimate reason, particularly when there are pressing needs and no other reasonable source of funds. However, even the TSP loan documentation warns borrowers about the impact a TSP loan can have on their retirement savings.

There are two distinct scenarios here:

Scenario 1: There are no other reasonable ways to borrow money outside of consumer debt, credit cards, or other high-interest forms of debt. In this case, the decision is straightforward, do you borrow against your TSP or not? If you have already exhausted your emergency savings and face unexpected essential expenses such as medical bills, a TSP loan may be a reasonable last resort, generally preferable to high-interest consumer debt, credit cards, or a TSP hardship withdrawal, which carries more significant tax consequences.

Scenario 2: You have other borrowing options, such as a home equity loan or HELOC, and need to determine which is the better choice. In this case, you need to compare the effective cost of each option.

The key concept here is that the effective borrowing rate of a TSP loan is not just the G-Fund rate. It is the opportunity cost: the growth rate of the money you borrow had it stayed invested. In other words, if you borrow money that would otherwise have been invested in the C-Fund, S-Fund, or I-Fund, your effective borrowing rate is the difference between the G-Fund rate and the return those funds would have generated over the loan period.

TSP Loan Opportunity Cost: A Real-World Example

To illustrate: imagine the Smiths had $100,000 in their TSP account five years ago, all invested in the Lifecycle 2040 fund. They borrow $50,000 for a five-year general purpose loan. At the G-Fund rate of 1.75% applicable at the time of this original example, a $50,000 loan amortized over five years results in a total of $2,256 in interest paid back to themselves.

Had that $50,000 remained in the L2040 fund, at a 10% average annual return, it would have grown to approximately $80,525 over that same period.

If instead the Smiths had borrowed through a home equity loan, at the average rate of approximately 7.53% as of May 2026, a similar loan amortization would have resulted in approximately $10,000 in interest paid to a lender. However, they would still have netted significantly more by leaving the TSP funds invested.

There are two additional considerations worth noting:

Leaving active duty. A TSP loan is only available while you are still employed. If you separate or retire, you must repay the loan in full, otherwise the IRS treats the outstanding balance as a taxable distribution subject to full taxation and potentially the 10% early withdrawal penalty. If you are approaching separation, make sure you understand all of your TSP rollover options before taking out a loan.

Tax treatment. TSP loan repayments are made with after-tax dollars, which differ from TSP contributions, which are pre-tax. Interest on a home equity loan may receive preferred tax treatment if you itemize deductions, an additional factor to consider when comparing options.

Portfolio asset allocation. This is the most significant impact of a TSP loan. Taking a loan effectively reduces your investment in higher-returning funds and locks that portion of your balance into the G-Fund rate for the duration of the loan, potentially creating a portfolio that is dramatically out of sync with your intended asset allocation and investment approach.

The truest danger of a TSP loan is this: taking a loan can dramatically alter your investment picture. Unless you account for the impact of locking in G-Fund returns on your loan balance, you risk creating a portfolio that no longer reflects your investment strategy.

Reason 2: The Borrower Believes They Have a Better Use for the Money

This section examines some of the most commonly cited reasons for taking a TSP loan to invest elsewhere.

Using a TSP Loan to Buy a Rental Property

Before determining whether a TSP loan makes sense for a rental property purchase, the more important question is whether the purchase itself makes sense. If the deal is genuinely strong, meaning the rental income will comfortably cover all expenses and hiccups along the way, a bank would likely be willing to finance it. If a bank will finance a good deal, there is no need to use your own retirement funds. One of the key benefits of real estate investing is the appropriate use of leverage.

If you are consistently being turned down by lenders, that may be a signal that the property is not as strong an investment as it appears, in which case using your retirement savings is even more risky.

Using a TSP Loan to Invest in Precious Metals

This is generally not recommended. Two key considerations:

• Tax treatment. Gold and other collectibles are taxed at a maximum rate of 28%, significantly higher than the 20% maximum long-term capital gains rate. And since TSP loan proceeds are invested outside the plan, the tax-deferred benefits of the TSP do not apply to those funds.

• Liquidity and value. Precious metals can be sold relatively quickly, but immediate liquidation typically results in receiving less than you paid. The market price of gold coins is their weight value, regardless of any collector premium, if you need to sell quickly.

Using a TSP Loan to Fund a Roth IRA

On the surface, this seems appealing, taking tax-deferred money and using it to fund a tax-free Roth IRA. However, there are important considerations:

First, since TSP loan repayments are made with after-tax dollars, the net effect is fairly similar to simply contributing to the Roth IRA directly. If you are in a higher tax bracket, foregoing the tax deferral on future TSP contributions to repay the loan in after-tax dollars effectively gives away your tax benefit. If you are in a lower tax bracket, maxing out the Roth TSP and a Roth IRA for both you and your spouse may be a more straightforward approach.

Second, before proceeding, understand what you plan to invest in with the Roth IRA that you cannot do inside the TSP. If the goal is simply to hold index funds, the TSP already does that at very low cost.

There is one scenario where this approach merits consideration, if you genuinely cannot afford to max out both accounts in a given year due to a one-time unexpected expense and expect to have sufficient cash flow to repay the loan and max out contributions the following year. However, this requires careful analysis of your cash flow situation before proceeding.

Remember that you cannot use TSP loan proceeds to exceed the IRS’s annual IRA contribution limits. For 2026, the Roth IRA contribution limit is $7,500 or $8,600 for those age 50 and older.

When Does a TSP Loan Make Sense?

TSP loans do have a legitimate place in personal finance, specifically when you need funds and have no other reasonable borrowing options. In that scenario, a TSP loan at the G-Fund rate is almost certainly preferable to high-interest consumer debt, credit cards, or a TSP hardship withdrawal.

However, the dangers of borrowing from your TSP to invest elsewhere are substantial:

• You risk losing money on the outside investment

• You risk underperforming what you would have earned had you left the money in your TSP

• You are jeopardizing your retirement savings on the outcome

• If you cannot repay the loan, it becomes a taxable distribution, subject to full income taxes and potentially the 10% early withdrawal penalty

If you do not pay yourself back, you do not owe yourself; you owe the IRS.

Before taking any TSP loan, consult with a fee-only financial planner who is familiar with federal employee benefits to ensure the decision aligns with your overall retirement strategy. If you have determined that a TSP loan is the right choice for your situation, see our guide on how to take a TSP loan for instructions on the process.