How lock periods, extensions, float-downs, and property timelines affect mortgage pricing.
What a lock does
A mortgage rate lock generally protects specified pricing for a defined period while the loan is processed, subject to the lock terms and the loan remaining materially consistent.
Lock period
Longer locks can cost more because the lender assumes market risk for more time. The right period should account for appraisal, underwriting, conditions, construction, and closing logistics.
Extension risk
If closing is delayed beyond the lock expiration, extension fees or repricing may apply. Responsibility for the delay can affect negotiations but does not automatically eliminate cost.
Float-down features
Some programs offer float-down features if market pricing improves. The triggers, fees, timing, and available improvement vary.
What can still change
A lock does not freeze property taxes, insurance, title charges, loan amount, program eligibility, or every closing-cost item.
Questions to ask before acting
- What assumptions could materially change the result?
- How much cash will remain after closing?
- What happens if taxes, insurance, repairs, or income change?
- Which terms should be confirmed in writing?
Bottom line
Use this guide as a framework for better questions and more complete comparisons. Actual eligibility, pricing, legal rights, and transaction requirements depend on the borrower, property, lender, program, contract, and location.