Interest Rate Arbitrage: How to Make Money From 0% Financing

Most people think 0% financing is about avoiding interest payments. You get the loan, pay it off over time, and feel good about not giving extra money to a bank.

That's a fine way to think about it. But there's a smarter play.

In 2020, I bought a Subaru during COVID. The manufacturer was offering 0% financing for seven years. Instead of paying cash (which I could have done), I took the 0% loan, invested that cash in U.S. Treasuries at about 4%, and watched it earn interest for the entire loan period.

The result? I earned roughly $5,000 by financing instead of paying cash.

This strategy has a name: interest rate arbitrage. And once you understand how it works, you'll never look at 0% financing the same way again.

What Is Interest Rate Arbitrage?

Interest rate arbitrage is the practice of borrowing money at one rate and investing it at a higher rate, then pocketing the difference.

In simple terms: you use cheap money (or free money, in the case of 0% loans) to earn returns on money you would have otherwise spent.

When someone offers you a 0% loan, they're essentially giving you free access to their capital for a period of time. If you invest your cash instead of spending it, you can earn returns on money that technically isn't even yours yet.

The math is straightforward:

• Borrow at 0%

• Invest the money you would have paid at a higher rate

• Make regular payments from your invested principal

• Keep all the interest you earned

It's not a get-rich-quick scheme. It's a methodical way to capture value that most people leave on the table. It's also one of the 101 money cheat codes we teach.

How I Earned $5,000 From a Subaru

Let me walk you through my actual example.

The Setup:

In 2020, car manufacturers were desperate to move inventory during COVID-19 uncertainty. Subaru was offering 0% financing for 84 months (seven years). I had the cash to buy outright, but I ran the numbers.

At the time, U.S. Treasury bonds were yielding around 4%. If I kept my cash invested instead of handing it to the dealer, that money could work for me for seven straight years while I made minimum monthly payments.

The Math:

For a roughly $30,000 vehicle financed at 0% and invested at 4% over 84 months minus loan interest: ~$5,000

The invested cash earned interest every year while I made my regular payments. By the time the loan was paid off, I had earned over $5,000 that I never would have seen if I'd paid cash upfront.

Same car. But I ended up with $5,000 more in my pocket.

Why does this work?

The dealer (or manufacturer's financing arm) doesn't care whether you pay cash or finance. They're making their money on the vehicle sale. The 0% offer is an incentive to get you in the door. Once they've sold the car, your financing choice doesn't affect their bottom line.

So you get free use of their money, and you get to earn interest on cash you keep invested. Everyone's happy.

How to Do This: A Step-by-Step Approach

Step 1: Find a Legitimate 0% (or low %) Financing Offer

True 0% financing deals are typically offered by:

• Manufacturer financing arms (Ford Credit, Toyota Financial, etc.) on new cars

• Appliance and furniture stores (promotional periods)

• Medical financing (CareCredit for procedures)

• Credit cards (0% intro APR periods)

For cars, these offers are often limited to specific models, trims, or inventory. The longest terms (60-84 months) typically require excellent credit.

Step 2: Confirm You Have Cash to Buy Outright

This strategy only works if you actually have the money to pay cash. You're not borrowing because you have to. You're borrowing because it's mathematically advantageous.

If you don't have the cash and you're financing because you can't afford the full price, that's a different situation entirely. You're not doing arbitrage. You're just buying something on credit.

Step 3: Do the Math and Keep Your Cash

Once approved for financing, do the math. During this step its critical that you confirm these conditions before going for it:

1. You already decided that you are going to purchase the item.

2. You cannot find a substantially lower price for the item elsewhere.

3. The cash price of the item does not offer a price discount larger than the interest rate arbitrage gain.

If all conditions are true, you have found a potentially good arbitrage opportunity. If you sign the paperwork, keep your cash invested instead of handing it over.

Use our Interest Rate Arbitrage Calculator to help you analyze the math in minutes.

Step 4: Invest the Cash in Low-Risk, Fixed-Income Assets

This is important: use reliable, fixed-income investments. You want predictable returns, not stock market volatility.

Options include:

• U.S. Treasury bonds (what I used): Backed by the federal government, highly liquid, predictable yields

• High-yield savings accounts: Currently paying 4-5% APY at many banks

• Certificates of deposit (CDs): Lock in rates for specific periods

• Treasury bills: Short-term government securities

I chose U.S. Treasuries because they're relatively dependable and the yields were attractive. You want your money earning returns, not riding the stock market rollercoaster while you owe on a car.

If you want to learn more about building a bond portfolio for this kind of strategy, check out our bond portfolio builder.

Step 5: Make Your Payments and Collect the Difference

Each month, your invested balance earns interest while you make your regular payment. As the loan progresses, your invested balance decreases (since you're using it to make payments), but you've been earning interest the whole time.

At the end of the loan term, the item is paid off, and you've pocketed all the interest earned. It won't work, however, if you miss payments and incur late fees and hits to your credit score. This must be avoided.

The Critical Caveat: Price Matters First

Here's where people mess this up: the purchase price has to be fair.

Interest rate arbitrage only works if you're already getting a good deal. If you overpay by $3,000 to get 0% financing, you've erased much of your arbitrage gain before you start.

The mistake I see:

Someone gets excited about 0% financing and buys an overpriced car, or chooses 0% financing over a significant cash rebate without running the numbers.

Example:

• Car A: $30,000 with 3% financing for 60 months

• Car B: Same car, $27,000 after $3,000 rebate

With Car A, you would earn ~$2,590 in interest at 4%. Net cost: $29,753.

With Car B, you pay $27,000 cash. Net cost: $27,000.

In this case, the cash deal wins.

Always compare:

• Total out-the-door price with 0% financing

• Total cost with cash rebates plus financing

• Run the arbitrage numbers on both scenarios

The price of the purchase comes first. Arbitrage is the bonus when you're already getting a fair deal.

Credit Score Requirements

Not everyone qualifies for 0% financing. Here's what you typically need:

• Minimum credit score: 720 (some require 750+)

• Credit score for best offers: 780+

• Other factors: Low debt-to-income ratio, stable employment, clean payment history

My credit score is well above 750, which has consistently helped me qualify for these offers. If your score isn't there yet, improving your credit is one of the highest-ROI financial moves you can make. If you want ideas for improving your credit score, get our 101 Money Cheat Codes free ebook.

What Can Go Wrong

Let me be honest about the risks:

1. Overpaying for the item
As I mentioned, if you accept a bad price to get 0% financing, you've defeated the purpose. Always negotiate the price independently of the financing terms.

2. Interest rates drop
If savings rates fall to 1-2% during your loan term, your arbitrage profits shrink. You won't lose money, but you won't gain as much. For this reason, there is an advantage to investing in short-duration fixed-income instruments so that you can pivot and pay off the loan if interest rates drop below your cost of financing.

3. Spending the money instead of investing it
If you take the 0% loan but blow the cash on something else, you've just taken on debt with nothing to show for it. This strategy requires discipline.

4. Missing payments on deferred-interest offers
Some "0% financing" offers (especially for furniture and appliances) are actually deferred-interest. If you don't pay off the full balance by the end of the promotional period, you get hit with all the back interest. Read the fine print carefully. The math can still work, but you have to subtract the deferred-interest from your gains.

5. Tax implications
Interest earned is taxable income. At a 22% marginal rate, $8,400 in interest means $1,848 in additional taxes. Your net benefit is still $6,552 but factor taxes into your calculations.

Other Applications Beyond Cars

I've used this approach with cars and houses, but it works anywhere you can find 0% or very low-rate financing:

Mortgage arbitrage: Borrow at a low mortgage rate and invest extra cash rather than paying off the house early. The math is more complex (and the timeline is 30 years), but the principle is identical.

Appliances and furniture: Buy a $3,000 appliance at 0% for 18 months, invest the $3,000, earn ~$200 in interest, pay off the balance before the promotional period ends.

Credit card intro offers: Use a 0% intro APR card for a major purchase, invest the cash you would have spent, pay off before the rate jumps.

The principle applies anywhere you can borrow cheaply and invest at a higher return.

Is This Right for You?

Interest rate arbitrage works when:

• You have the cash to pay outright

• You have excellent credit (750+)

• You're disciplined enough to invest the money and not spend it

• You're already getting a fair price on the purchase

• You're comfortable managing the mechanics (investments, payments, timelines)

It doesn't make sense when:

• You'd spend the cash instead of investing it

• Your credit won't qualify you for a low rate

• The 0% offer is only available on overpriced inventory

• You have high-interest debt you should pay off first

The Bottom Line

Most people hear "0% financing" and think: great, no interest charges.

That's leaving money on the table.

When you understand interest rate arbitrage, you realize that 0% financing is actually an opportunity to earn returns on capital you'd otherwise spend. It's one of the cleaner ways to put your money to work without taking on real risk.

For my Subaru, that understanding was worth $5,000 over seven years. Not life-changing money, but real money that required zero additional effort once I set it up.

Get started with your interest rate arbitrage analysis with our free calculator:

This article is for educational purposes and reflects one approach to financing decisions. Interest rates, tax situations, and individual circumstances vary. Consider consulting a financial professional for advice specific to your situation. This is not investment advice.