Execution, delivery, rent commencement: 3 start dates, not one field

A lease has at least 3 start dates and they are rarely the same day. Execution is when the parties signed and became bound. Commencement is when the term starts running, which in many leases is the day the space is delivered. Rent commencement is when the tenant first owes money.

They diverge because the gap between them is negotiated. A tenant that signs in January, takes keys in April and opens in July has 3 dates spread over 6 months, each driving something different.

What each date actually marks

• Execution. The parties are bound. Obligations that do not wait for possession start here: the deposit, insurance, confidentiality, and the landlord's obligation to carry out its works.
• Delivery and commencement. Possession passes and the term clock starts — but only if the lease says commencement is delivery. Some leases fix commencement as a calendar date and treat late delivery as a separate remedy, so this field has to be read, never inferred.
• Rent commencement. Billing starts. It is often expressed as a rule rather than a date: the earlier of a stated number of days after delivery, or the day the tenant opens for business.

A fourth date, opening for business, does not start the term but frequently triggers rent commencement and continuous-operation obligations. Where it does, it belongs in the record as its own field.

Which clock hangs off which date

Row 2 is where portfolios lose money. Option windows are counted back from expiry, expiry is counted from commencement, and a system that stored the rent start as commencement computes an option deadline months adrift — the error class in what counts as a critical date.

When delivery slips, which dates move with it

Landlord works run late more often than not, and the lease anticipates it. Delivery moves, commencement moves with it where commencement is defined as delivery, and rent commencement moves too where it is an offset. Expiry usually moves as well, because the term is a duration rather than a fixed end date — but not always, and a lease with a fixed expiry and a floating start is shorter than the one everyone thinks they signed.

Many leases also carry an outside date: if delivery has not happened by then the tenant gets a remedy — rent credit, a termination right, sometimes both. It is a critical date in its own right, and the one nobody abstracts, because until delivery slips it looks hypothetical.

Free rent moves the invoice, not the term

Abatement is the most misfiled of the lot. Three months free from rent commencement does not change when the term started, when it ends, or when an option window opens. It changes which months carry a charge.

1. Record rent commencement and the abatement period as separate fields — the date the obligation starts, and the months in which the charge is suppressed.
2. Record what abatement covers. Free base rent with operating expenses still payable is a different invoice from a full holiday, and this is where a reconciliation later goes wrong, as in a CAM true-up statement.
3. Keep expiry derived from commencement, never from the first billed month.
4. Note whether abatement is forfeitable on default, because that turns a schedule into a conditional one.

Accounting is the other consumer. Lease accounting standards recognise rent over the term rather than as invoiced, so the term start and the billing start feed different systems — confirm the treatment against your own accounting policy rather than assuming the billing date carries across.

A single start date is not a simplification. It is 3 answers averaged into one, and wrong for all 3 questions.

Why the error surfaces years later

Date errors stay silent while rent is paid on time. They surface at an estoppel request, when the landlord's stated commencement date and the tenant's record disagree in writing — the conflict examined in when the abstract and the estoppel disagree. They surface again when a conditional rent state is triggered and nobody can say which month it started, which is why co-tenancy has to be stored as a rule and why sales-based rent needs an unambiguous breakpoint and reporting period.

The fix is unglamorous: 4 date fields instead of one, each with its citation, plus the rule wherever a date is derived. Fixing that schema before extraction starts is the point of building the record properly, the kind of work described under MVP and product builds. Siblings sit in lease abstraction and document AI, inside our work with real estate teams.

• lease dates
• lease abstraction
• rent commencement
• critical dates