The rent roll is a document the seller made. The estoppel certificate is a document the tenant signs. When the two disagree, and they do more often than most investors expect, the tenant's version is the one you will be living with.
Buying an occupied rental is one of the easier occupancy situations because the occupants have a right to be there and everyone knows the rules. It goes wrong when the buyer verifies the property carefully and the tenancies barely at all.
You Are Buying the Leases Too
Start from the principle that governs everything else: a lease generally survives the sale. The tenant's agreement runs with the property, and you step into the landlord's side of it.
So you cannot raise the rent because you paid more than the last owner. You cannot decline to renew where local rules require cause. You cannot change the terms mid-term, and you inherit whatever the previous landlord agreed to, including things that never made it into the written lease.
That last point is where the money hides. A verbal agreement that the tenant handles the yard in exchange for a lower rent, a promise to replace the furnace next spring, a side arrangement about the garage. None of it appears in the seller's paperwork, all of it is real to the tenant, and you will hear about it in month two.
Regulated units are the large exception to all of this, and they are covered in rent controlled and stabilized units. Subsidized tenancies carry their own transfer paperwork, per voucher tenants in place. Month-to-month tenancies give you more room, since terms can generally be changed with proper notice. How much notice, and whether cause is required to end the tenancy at all, is entirely local and is not something to assume from a prior market.
The Estoppel Certificate
This is the single highest-value document in the transaction and a large share of investors skip it.
An estoppel certificate is a short statement the tenant signs confirming the actual facts of their tenancy: the rent, when it is due, what deposit the landlord holds, when the lease started and ends, whether any rent is prepaid, whether the landlord owes them anything, and whether any agreements exist outside the written lease.
Its power is in the name. Once the tenant has confirmed those facts in writing, they are generally held to them, which prevents the conversation where the tenant explains after closing that the previous owner agreed to something quite different.
Send one to every tenant during your inspection period and get them back before you waive contingencies. Where a tenant refuses to sign, treat that as information rather than an inconvenience: something about that tenancy is not what the seller described.
Read the returned certificates against the rent roll line by line. A mismatch on deposit amounts is common and cheap. A mismatch on lease end dates, prepaid rent, or a promised repair is a price adjustment, and finding it now is the whole point of the inspection period.
Verify the Income, Not the Claim
A rent roll shows what the leases say. It does not show what arrives.
Ask for twelve months of bank statements or a ledger showing actual deposits, and reconcile them against the roll. What you are looking for is the gap between scheduled and collected: a tenant three months behind, a unit that was vacant for a stretch, a rent that was quietly reduced.
Ask specifically about concessions. Free months, reduced rent in exchange for something, deferred balances on a payment plan. These are the routine ways a stated rent becomes a different real rent.
Then run the units against actual market rents rather than the seller's optimism, per estimating rent for an investment property. Below-market rents are often the reason the deal is attractive, and they are only an opportunity if the local rules and the lease terms let you move them. Underwrite what you can legally collect on a realistic timeline, per analyzing a real estate deal.
Deposits, and the Closing Mechanics
Security deposits are the tenant's money held in trust, not the seller's cash. They transfer to you at closing, normally as a credit, and from that moment you are the one who must account for them.
Get the exact figures in writing per unit, cross-checked against the estoppel certificates. Where state law requires deposits held in a specific kind of account, or requires interest to be paid, confirm what was actually done, because inheriting a mishandled deposit does not inherit a defense.
Prepaid rent and last month's rent need the same treatment, with a proration at closing so you are not collecting rent someone already paid.
Practical items for the closing itself: get the original signed leases rather than summaries, get the tenant contact details, get the maintenance history, and get keys for every unit. Then send tenants a written notice of the change in ownership with the new payment instructions, which several states require in specific form and which prevents a month of rent going to the wrong place. Coordinate the prorations properly, per the closing process step by step.
What to Check Beyond the Paperwork
Get inside every unit. Sellers resist this and it is the thing to insist on, because the unit you were not shown is the unit with the problem, and an occupied inspection tells you about both the property and the tenancy.
Check that the occupants match the leases. Extra adults not on the agreement, a subtenant, a short-term guest arrangement running out of a unit. Each of those is a different problem and none appear on paper.
Confirm whether any unit is occupied by the seller's relative at a courtesy rent, which is common and ends badly once ownership changes.
Ask about pending disputes, complaints and repair requests. An unresolved habitability complaint is a liability you are buying, and so is a tenant who has already retained a lawyer.
And check the units against local rental registration or licensing requirements, since many jurisdictions require registration, periodic inspection, or a certificate of occupancy for rentals, and non-compliance can limit your ability to collect rent or evict until cured.
If Your Plan Requires Them Gone
Some buyers want the units, not the tenancies, and that is a different transaction that has to be structured up front rather than discovered afterward.
A fixed-term lease does not end because the property sold. You wait it out, you negotiate an early surrender, or you have a cause that the local rules recognize. Wanting to renovate is not automatically one of them.
Even on month-to-month tenancies, the notice period is set by state law and is longer than most investors assume, sometimes considerably longer for a tenant of long standing. A growing number of cities also require just cause to end any tenancy, and some require a relocation payment to the departing household on top of the notice.
So the honest sequence is: establish the actual lease end dates, establish the local notice and cause rules, and only then decide whether the vacancy plan is viable. Where it is not, either the numbers work with the tenants in place or the deal is not for you.
Where you do want vacancy, a negotiated surrender is nearly always faster and cheaper than waiting or filing. Offer it early, in writing, and to everyone rather than selectively, since selective offers create fair housing exposure of the kind set out in fair housing for real estate investors.
Where the Real Upside Sits
Occupied rentals with below-market rents and a disengaged owner are one of the more reliable value-add situations available, and they overlap heavily with the seller profile in tired landlord leads.
The upside comes from operating the property properly rather than from anything structural: rents brought to market as leases turn over and rules allow, expenses that were being paid without being managed, maintenance done on a schedule instead of on emergency call-outs, and vacancy reduced by actually answering the phone.
What kills that thesis is buying it as though the transition is free. Some tenants leave when the ownership changes and some units come back needing work. Budget turnover into the first twelve months rather than assuming the rent roll continues uninterrupted. That modeling error runs throughout the BRRRR analysis.
The guide to motivated seller niches covers where an occupied purchase fits against the vacant ones.
Put This in Your Contract Template
Put estoppel certificates into your standard contract language for every occupied purchase, returned and reviewed before your contingency expires.
It costs nothing, the seller cannot reasonably object, and it converts the riskiest unverified part of the transaction into signed statements from the people who actually know. Almost every occupied-purchase horror story in this business traces back to a fact the tenant knew and the buyer never asked about.