Lease Option vs Subject To: Which One and When
You've got a seller in front of you and two ways to structure the deal. One keeps them on the mortgage. One doesn't put you on title at all. You need to know which one fits this specific house, this specific seller, before you make an offer you can't unwind.
Here's the short answer. Use subject-to when there's an existing mortgage with a good rate or terms you want to keep, and the seller is fine walking away from the loan while you take title and make the payments. Use a lease option when the seller has no mortgage to inherit, or when you don't want the liability of title yet, or when the numbers only work if you control the property without owning it. The dividing line is almost always the existing loan. If there's cheap debt worth keeping, subject-to. If there isn't, or the seller won't let go of title, lease option.
What each one actually does
Subject-to means you take the deed. The property is yours, recorded in your name at the county. The mortgage stays in the seller's name and you make the payments on their loan without formally assuming it. You own the house. You don't own the debt on paper, but you're the one paying it.
A lease option is two documents stapled together: a lease, and a separate option to buy at a set price within a set window. You don't get the deed. You get the right to buy later and the right to occupy or control the property now, usually by subletting it to a tenant-buyer at a markup.
That's the whole distinction. Title now versus title later. Everything else, the risk, the tax treatment, the exit, follows from that one fact.
A real example, same seller, two different deals
Say a seller owns a house worth $310,000. She inherited it from her father, doesn't want to landlord it, and needs $20,000 to cover a move and some medical debt. There's a mortgage on it: $214,000 balance, 3.4% rate, $1,380 a month payment.
Subject-to fits here. You take the deed, hand her $20,000 at closing, and keep making her $1,380 payment. You rent the house for $2,200 a month. After the mortgage payment, taxes, and insurance, you're clearing somewhere around $650 to $700 a month before repairs and vacancy. And you've got a 3.4% rate on $214,000 that you could never get from a bank today. That rate is the whole reason the deal is worth doing.
Now change one fact. Same seller, same house, but it's free and clear. No mortgage. She still wants $20,000 up front and doesn't need or want to sell outright this year because of how the sale would hit her taxes. There's no debt to inherit, so subject-to doesn't apply. A lease option does. You give her $5,000 in option money, lease the house from her at $1,600 a month for three years with $400 of that credited toward a future purchase price of $315,000. You then place a tenant-buyer in the house at $2,100 a month. Your spread is $500 a month while you hold it, plus whatever equity shows up if the tenant-buyer exercises and you flip your option to them at a markup.
Same seller archetype, same rough equity position, two completely different structures, because the loan situation flipped.
Why the mortgage is the deciding factor
With subject-to, you're stepping into someone else's financing. That only makes sense if the financing is worth stepping into: a rate below market, a balance low enough that your equity cushion is real, and a seller who understands and accepts that the loan stays in their name while you make the payments. If the rate is 7.8% and market rate is 6.5%, there's no reason to take on that liability. You'd be better off with a lease option or just walking.
With a lease option, there's no loan to inherit because there isn't one, or the seller won't quitclaim the deed to you under any structure. Lease options also make sense when you're not sure yet whether the deal pencils long term and you want a cheaper way to control the property while you find out, since you're not taking on the deed, the property taxes as owner of record, or the liability that comes with title.
What people get wrong
The most common mistake is choosing the structure based on which one they've heard of more, not which one the deal calls for. Someone reads about subject-to online, gets excited, and tries to force it onto a free-and-clear property where a lease option would be simpler and lower risk. Or someone defaults to lease options out of habit and leaves a 3% mortgage on the table that they should have taken subject-to.
The second mistake is not asking the seller directly and early: is there a mortgage, what's the balance, what's the rate, and are you okay staying on that loan while I make the payments. That one conversation, in the first call, tells you which structure to bring to the table. Waiting until you're drafting paperwork to find this out wastes everyone's time.
The third mistake is treating the two as interchangeable paperwork choices instead of different risk profiles. They are not the same deal with different names on it.
The honest limitation
Subject-to carries real due-on-sale risk. The mortgage almost certainly has a clause letting the lender call the full balance due if title transfers without their approval. In practice, lenders rarely call a performing loan just because the county recorder shows a new owner. But "rarely" is not "never," and if the loan does get called, you need a plan to refinance or sell fast. Anyone telling you this risk doesn't exist is selling you something. Go in with your eyes open and have a backup plan for the loan getting called.
Lease options have their own soft spot: you don't control the title, so a seller can still put a lien on the property, let it go to foreclosure if they have another mortgage you don't know about, or simply refuse to close when your option comes due. Get everything recorded properly and get title insurance or an attorney's eyes on it before you hand over option money.
Figuring out which structure fits a specific seller conversation is exactly the kind of decision that gets easier once you've run the numbers on a few dozen of these instead of two or three. That's what Deal Machine is built for, running the seller's actual numbers, mortgage or no mortgage, and showing you which structure the deal is telling you to use before you make an offer. You can find it at readmoneydecoded.com/deal-machine.