The core issue
How a New Home Deposit Contribution Affects Your Mortgage
When a developer offers you a deposit contribution or incentive package, the lender does not treat it as money in your pocket. Instead, the lender deducts the declared contribution value from the effective purchase price, which produces a higher LTV than you expected.
The practical effect: a first-time buyer with a 10% cash deposit who receives a 5% developer cash contribution is typically assessed as a 90% LTV purchase with the contribution noted separately. Not as an 85% LTV purchase. The contribution does not move you into a lower LTV band. It stays visible as a declared incentive and the maximum mortgage is calculated against your own cash deposit.
This is the bit developer sales teams rarely explain. The numbers they present assume the contribution adds to your position. The lender's assessment often works differently.
Do not accept any contribution before speaking to a broker
Developer sales teams present incentives as straightforward benefits. Each contribution type carries specific declaration requirements and LTV implications that can change the mortgage you are able to get. Accepting a contribution verbally or in writing before understanding the mortgage impact can leave you committed to a purchase where the finance no longer works as expected.