A mortgage offer is a conditional commitment with a deadline, not a guarantee. Knowing which conditions remain outstanding is what prevents surprises near completion.
The Stages Before an Offer
There are three distinct stages and they are frequently confused. An affordability check or eligibility indication is informal and based on information you supplied. An agreement in principle is a soft assessment indicating what a lender would probably lend. A formal offer follows a full application, verification and valuation. Only the formal offer is a commitment, and even then it is conditional. The earlier stages are useful for planning and for showing an estate agent that you are credible, but they are not binding on the lender and the terms can change when the full application is assessed.
This matters because the gap between an agreement in principle and a formal offer is where applications fail. Income verified lower than declared, an undisclosed debt appearing, a credit file issue or a valuation below the purchase price are the common causes.
Treat the agreement in principle as a planning figure and do not commit to anything irreversible on the strength of it. The formal offer is the document that lets you proceed with confidence.
What the Offer Document Contains
The offer states the amount, the rate, the term, the monthly payment, the product details including any fixed period, the early repayment charges and the conditions that must be satisfied before funds are released. All of it is worth reading, and the conditions section most of all. Check the figures against what you were quoted. The amount, rate, term and payment should all match your notes, and transposition errors or last minute product changes are not rare. The signed documentation governs rather than the conversation.
Note the expiry date. Offers are typically valid for three to six months, and a delayed transaction can outlast one, requiring a new application with a fresh assessment at whatever rates then apply. This is a real risk in slow chains.
Check the early repayment charge structure and the reversion rate at the end of any fixed period. Those two determine your flexibility and your cost in a few years, and they are easy to skip when the focus is on completing the purchase.
The Conditions That Still Have to Be Met
Common conditions include a satisfactory valuation, proof of the deposit source, buildings insurance in place from completion, confirmation of employment, and sometimes specific repairs or retentions where the valuation flagged a problem. Each must be resolved before funds are released. Valuation conditions are the most consequential. A valuation below the purchase price means the lender will lend against the lower figure, leaving you to find the difference or renegotiate. A valuation flagging structural issues can produce a retention, where part of the funds are held until the work is done.
Source of deposit documentation is the most commonly underestimated. Lenders must verify where the money came from, which means documented evidence for any large credit to your account, and a letter confirming that family assistance is a gift rather than a loan.
Employment confirmation is usually a formality and becomes a problem if your circumstances change between application and completion. A job change, a move to self employment or a period of leave can all invalidate the offer.
What Can Still Go Wrong
A lender can withdraw an offer if circumstances change materially before completion. New borrowing, a missed payment, a change of employment or a significant change in the property’s condition are the usual triggers. Avoiding all of them for the duration is the simplest advice available. New credit applications during this period are the most common self inflicted problem. A car loan, a new card or a store finance arrangement taken between offer and completion changes the affordability picture and can cause a withdrawal. Nothing new should be taken on until the keys are collected.
Keep paying everything on time, including small accounts. Lenders frequently re check credit files before releasing funds, and a late payment at that moment is expensive in a way no one anticipates.
Where something does change, tell the broker or lender rather than hoping it goes unnoticed. Disclosed changes are often manageable and discovered ones rarely are.
Between Offer and Completion
Arrange buildings insurance to start from the date of exchange or completion as the lender requires, since this is a condition and the transaction cannot complete without it. It is also the point at which the risk legally becomes yours in many jurisdictions. Keep all the documentation accessible. The conveyancer, the lender and the broker will each request items, sometimes repeatedly, and having the pack ready turns a multi week exchange into a short one.
Diarize the offer expiry and the end of any fixed rate period immediately. The second is the more valuable reminder, because reverting silently to a standard variable rate years later is among the most common and most expensive passive financial outcomes.
Finally, do not rely on a completion date until contracts are exchanged. Before that point either side can withdraw in most jurisdictions, and committing to removal costs or notice on a rental in advance of exchange is where people lose money on transactions that do not complete.
The short version is to read the conditions rather than the headline figures, diarize the expiry and the end of the fixed period, and change nothing about your finances until completion. Those three cover almost every way a formal offer fails to turn into a mortgage.
