Jumbo Loans: What They Are and When You Really Need One

A few summers ago my cousin tried to buy a condo in San Francisco for 1.2 million. He had a good credit score, a solid down payment, and a stable tech job. He walked into a lender assuming the loan would be routine. It was not. He was looking at a jumbo loan, and the rules were different enough that he had to go back to the drawing board on his budget.

Jumbo loans sit outside the regular conforming mortgage market. They work differently, cost differently, and come with more scrutiny. If you are shopping in an expensive market, you probably need to understand them.

The conforming limit, briefly

Every year the Federal Housing Finance Agency sets the conforming loan limit, the maximum size of a mortgage that Fannie Mae and Freddie Mac will buy. For 2026 the baseline is 832,750 for a single family home. In high cost counties, like most of California, parts of the Northeast, Hawaii, and Washington DC metro, the limit goes up to 1,249,125 or similar depending on the specific county.

Any loan amount above these limits is considered jumbo, meaning non conforming. The lender either keeps the loan on their own books or sells it in a private market, not to Fannie or Freddie. Because the government backed buyers do not purchase these loans, the risk sits more directly with the lender, and that changes everything about how they underwrite.

When you actually need a jumbo loan

The simple test is this. Take the purchase price, subtract your down payment, and see if the result is above the conforming limit for the county. If yes, you need a jumbo loan or you need to put more money down to bring the loan amount under the threshold.

For example, a 1,000,000 home in a county with an 832,750 conforming limit would need 167,250 down to stay conforming. If you only have 100,000 to put down, your loan amount is 900,000, which is jumbo territory.

My cousin's option in San Francisco was slightly different. The San Francisco high cost limit is around 1.2 million. His 1.2 million purchase price with twenty percent down meant a 960,000 loan, which stayed conforming. He stuck with a regular conventional loan, which saved him money. If his purchase price had been 1.3 million with the same down payment, he would have been jumbo.

Credit score matters more

Conventional loans usually accept credit scores of 620 and up. Jumbo lenders typically want 700 or higher, often 720 or 740 to get competitive rates. Below 680 you will struggle to find a jumbo lender willing to even look at your application.

Down payment is almost always bigger

For a conforming conventional loan you can put as little as 3 percent down. For a jumbo loan, most lenders want 10 to 20 percent down. Some will go to 10 or even 5 percent for strong borrowers, but you will pay for it in rate and fees. Twenty percent is where you get the best terms.

Reserves after closing

This is the one most people do not expect. Jumbo lenders usually want you to have significant cash reserves left after closing. The industry standard is six to twelve months of mortgage payments sitting in liquid accounts, after you have paid your down payment and closing costs.

For a 950,000 jumbo loan with a 7,500 monthly payment, that is 45,000 to 90,000 in reserves on top of your down payment. The lender wants to know that if you lose your job or hit a rough patch, you can keep making payments.

Debt to income is stricter

Conventional loans will often approve a DTI up to 45 percent, sometimes higher with compensating factors. Jumbo lenders typically cap DTI at 43 percent, and the best rates go to borrowers under 38 percent. If your student loans, car payment, and credit cards are eating a big chunk of your income, you might not qualify at all.

Interest rates, surprisingly competitive

In the past, jumbo rates were higher than conforming rates. For the last decade or so, that has flipped. Jumbo rates are often slightly lower than conforming because jumbo borrowers tend to have stronger profiles and the loans are often held in portfolio by big banks that want the business.

The spread varies by lender. Shop at least three places if you are getting a jumbo loan. The pricing differences between banks can be substantial, half a percent is common.

PMI on jumbo loans

Standard conventional loans require PMI if you put less than twenty percent down. Jumbo loans sometimes have PMI, sometimes not. Many lenders avoid PMI by using piggyback structures or by pricing in the risk through a slightly higher rate.

A common structure is the 80 10 10. You take a first mortgage for 80 percent of the purchase price, a second mortgage or HELOC for 10 percent, and put 10 percent down. The first mortgage stays conforming or jumbo, no PMI needed, and the second lien covers the gap. This is more complex paperwork but can save money for borrowers who do not want to put twenty percent down.

Documentation is heavier

Prepare for a lot more paperwork than a conforming loan. Jumbo underwriters will want two years of tax returns, usually with all schedules. Two months of statements for every asset account. Explanation letters for any large deposits. Pay stubs covering the most recent 30 days. If you are self employed, add a profit and loss statement and sometimes a letter from a CPA.

Closings tend to run 45 to 60 days instead of 30. Build that into your contract timeline.

When to consider piggyback instead

Instead of one big jumbo loan, some buyers split the financing. A conforming first mortgage up to the limit, then a smaller second mortgage or home equity line of credit on top. This can qualify as two separate loans with potentially better rates than a single jumbo, especially if the first loan is well under the jumbo threshold.

My cousin considered this. In the end he stayed with a single conforming loan after bumping his down payment up by 60,000 that his parents helped with. Different paths lead to the same house.

Who actually benefits from jumbo

Jumbo loans make the most sense for buyers in genuinely expensive markets who have the income and reserves to support a big payment and want a single clean loan. If you are buying a 2 million house in Manhattan or a 1.8 million house in Palo Alto, jumbo is the obvious fit.

For buyers hovering just above the conforming limit, consider whether a slightly higher down payment or a piggyback structure gets you better terms. Running the two scenarios through a lender can save thousands over the life of the loan.

The main thing is not to assume all mortgages work the same way. The rules change above the conforming limit, and the rules of the game are stricter.