A float down rate lock is a mortgage rate lock with an added option: your rate is protected against increases the way any lock protects you, but if market rates fall far enough before closing, you can drop your rate one time. You pay a fee upfront for that flexibility, and the original locked rate stays as your worst case no matter what the market does.
How the Option Works Alongside a Standard Lock
A standard rate lock commits the lender to holding your rate for a set period, usually 30, 45, or 60 days, while your loan is underwritten. That locked rate becomes your ceiling. If rates climb, you’re covered. If rates drop, you watch the savings go by.
Adding a float down changes the second half of that equation. The lock still shields you from increases, and the lender also agrees to let you reduce your rate once if market conditions improve enough before closing. Most lenders limit the float down to a single use, though a few allow two adjustments during the lock period.
Either way, the original locked rate remains your floor of protection. If rates stay flat or rise, you close at what you locked. If rates fall enough, you exercise the option and close lower. You never pay more than the original lock.
Conditions for Exercising the Float Down
Small dips won’t trigger anything. Lenders set a minimum threshold that market rates must fall below your locked rate before the option becomes available, and that threshold is almost always at least 0.25 percentage points. Day-to-day fluctuations won’t qualify.
Timing is equally strict. The float down window typically opens after your loan receives conditional approval and closes a set number of days before your scheduled settlement. Inside that window, you contact your loan officer and request the adjustment. The lender checks the request against its current rate sheet to confirm the drop meets the contract’s threshold.
If rates haven’t dropped enough when you make the request, or if you miss the window, your original locked rate stays in effect. The rate you get comes from the lender’s published rates at the moment your request is processed, not from any outside index you might be watching.
What It Costs
The fee typically runs between 0.25% and 1% of the loan amount, paid upfront when you add the option to your rate lock. On a $400,000 mortgage, that’s $1,000 to $4,000. Some lenders build the cost into your locked rate instead as a small premium, often around 0.125%, rather than charging a flat fee.
The fee is almost always nonrefundable. If rates never fall enough to trigger the float down, you’ve paid for protection you didn’t use, and the money doesn’t come back. That’s the central gamble: you’re buying insurance against a specific scenario, and like any insurance, it costs something whether or not you file a claim.
When the option is exercised, some lenders also cap how much of the rate drop actually reaches you. If rates fall 0.50%, the lender might pass along only 0.375% of that improvement and keep the rest. Specifics vary by lender and loan program, so read the lock agreement closely before paying.
Float down fees show up on your Loan Estimate under Section A as part of origination charges, alongside items like processing fees and underwriting fees.1Consumer Financial Protection Bureau. What Are Mortgage Origination Services? What Is an Origination Fee?
When Paying for It Makes Sense
The math is simpler than it looks. Divide the upfront fee by the monthly payment savings the lower rate would produce. That gives you a breakeven timeline in months. If you plan to keep the loan longer than that, the float down pays for itself. If you’re likely to refinance or sell within a few years, the fee probably isn’t worth it.
Say the fee costs $1,500 and a 0.25% rate reduction saves you $60 per month. You’d need 25 months to break even. On a loan you plan to hold for ten years, that’s a clear win. On a starter home you expect to sell in three years, the margin is thinner and depends on whether rates actually drop enough to trigger the option in the first place.
The option makes the most financial sense in two situations: when you’re locking during a period of clearly declining rates and want to capture further drops, or when your lock period is unusually long. In a stable or rising-rate environment, you’re paying for something you’ll almost certainly never use.
New Construction and Extended Locks
Float down provisions become especially relevant when you’re building a home. New construction timelines stretch well beyond the standard 30- to 60-day rate lock period.2Consumer Financial Protection Bureau. What’s a Lock-In or a Rate Lock on a Mortgage? A house that takes eight or ten months to complete exposes you to real rate risk. Extended locks of 180, 270, or even 360 days exist for these situations, and many come with a built-in float down option.
The logic follows: locking for nearly a year at a fixed rate means a lot can change. Lenders know borrowers won’t commit to a long lock without some downside protection, so builder rate lock programs frequently include a one-time float down exercisable within 30 days of closing. The trade-off is that extended locks start at higher rates than short-term locks to compensate the lender for carrying the risk longer.
If you’re buying new construction, ask specifically about builder lock programs. These are often separate from the standard float down add-on and may have different fee structures and timing rules.
FHA, VA, and USDA Loans
Float down provisions aren’t limited to conventional mortgages. FHA, VA, and USDA loan programs all allow them, though the specific terms depend on the lender rather than the agency backing the loan. Neither FHA nor VA publishes a standardized float down policy; each lender sets its own rules within program guidelines.
What you’ll commonly see across government-backed programs mirrors conventional float downs: a minimum rate drop of 0.25%, a fee of roughly a quarter-point, and a one-time exercise window that closes some number of days before settlement. Confirm availability with your lender before assuming the option is on the table for your loan type. Not every lender offers it across all programs.
Alternatives to Paying for a Float Down
The float down isn’t your only option when you’re worried about locking too early.
- Wait to lock. You can delay locking until closer to closing. This leaves you fully exposed to market movement in both directions, but it’s free. If you’re confident rates are headed lower and your closing date is soon, floating without a lock avoids the fee entirely.
- Ask the lender to renegotiate. Some lenders will voluntarily re-lock you at a lower rate if the market drops significantly, even without a formal float down provision. They have no obligation to do this, but the threat of losing your business to a competitor gives them incentive. It costs nothing to ask.
- Shorter lock period. A 30-day lock costs less than a 60-day lock and gives rates less time to move against you. If your closing timeline is tight, a short lock without a float down may be the simplest approach.
A standard rate lock carries no additional fee in most cases.2Consumer Financial Protection Bureau. What’s a Lock-In or a Rate Lock on a Mortgage? Adding the float down introduces cost and complexity. For borrowers in a stable rate environment with a short closing timeline, skipping it is often the right call.
If Your Lock Expires
If closing gets pushed past the end of your lock period, the locked rate disappears. You’re then exposed to whatever the market is doing, and extending the lock typically costs extra. The CFPB notes that extending a rate lock can be expensive, and lenders aren’t required to disclose extension fees on the original Loan Estimate.2Consumer Financial Protection Bureau. What’s a Lock-In or a Rate Lock on a Mortgage? Ask about extension costs before you lock so you aren’t surprised if the timeline slips.
A float down doesn’t protect you from lock expiration. If your lock expires and you need an extension, you’ll pay the extension fee on top of whatever you already paid for the option. This is another reason the float down is most useful with longer lock periods, where the lock is less likely to expire before closing.
What Changes in Your Paperwork
When a rate changes during the loan process, federal disclosure rules require the lender to update your documents. Under the TILA-RESPA Integrated Disclosure rule, if the interest rate wasn’t locked when the original Loan Estimate was issued and is later locked, the lender must provide a revised Loan Estimate within three business days showing the new rate, updated points, lender credits, and any other charges tied to the interest rate.3eCFR. 12 CFR 1026.19 – Certain Mortgage and Variable-Rate Transactions
A float down adjustment to an already-locked rate is slightly different, since the rate was already locked once. In practice, lenders issue either a revised Loan Estimate or an updated Closing Disclosure reflecting the lower rate, the recalculated monthly payment, and any changes to closing costs. The specific document depends on where you are in the timeline and how the lender processes the change. Either way, you’ll see the updated numbers in writing before you sign anything at settlement.
Tax Treatment
Float down fees are generally not deductible as mortgage interest. The IRS allows you to deduct mortgage “points” only when the charge represents prepaid interest paid for the use of money. Amounts paid for specific services connected to getting the loan, like appraisal fees, notary fees, and mortgage preparation costs, don’t qualify.4Internal Revenue Service. Publication 936, Home Mortgage Interest Deduction
A float down fee is a charge for optionality, not prepaid interest. It buys you the right to adjust your rate, which puts it closer to a service fee than to discount points. The IRS doesn’t address float down fees by name, but the general framework makes deductibility unlikely. If you’re counting on a deduction to justify the cost, talk to a tax professional before you pay.