Lock It or Let It Ride? Mortgage Rate Strategies for San Antonio Move-Up Buyers Who Must Sell First

If you’re a move-up buyer in San Antonio, you’re doing two big things at once: selling your current home and buying your next one. That’s exciting… and it’s also the fastest way to feel like your calendar is running your life.

In early 2026, mortgage rates are still a major part of the decision. Freddie Mac’s weekly survey showed the average 30-year fixed rate at 6.09% as of January 22, 2026. (Freddie Mac) That number matters because even small rate changes can shift your monthly payment—and for move-up buyers, that can affect what you can comfortably afford and how you time your sale.

At the same time, our local market has been more buyer-friendly than the last few years. Recent SABOR reporting showed months of inventory around 6 months and days on market in the 80s in late 2025, which often means buyers take more time and sellers need a stronger plan. (Sabor)

So the big question becomes:

When you buy your next home, do you lock your rate or float it?

As a Realtor with 18 years helping buyers in San Antonio, I’ll walk you through this in plain language—so you can make a smart call without needing a finance dictionary.

Locking vs. Floating: The Simple Version

What “locking” your rate means

A rate lock is your lender saying: “This is your interest rate, and it won’t change as long as you close before the lock expires.” Zillow notes locks are commonly 30, 45, or 60 days, though they can be shorter or longer. (Zillow)

Locking is usually best when you want certainty. You’re trading a little flexibility for peace of mind.

What “floating” your rate means

Floating means you don’t lock yet. Your rate can move up or down until you choose to lock.

Floating is not “wrong.” But it is riskier—especially when you’re also trying to time a home sale.

Why Move-Up Buyers Have a Harder Version of This Decision

Most buyers only need one closing. You need two.

That creates two common problems:

1. Your purchase closing can shift if your sale closing shifts.
2. Your budget can get squeezed if rates rise while you’re floating.

In a market where homes can take longer to sell, timing becomes the whole game. (Sabor)

The Best “Middle Ground” to Ask About: Float-Down Options

If you like the safety of locking but don’t want to miss a possible drop, ask your lender about a float-down option.

Float-downs vary by lender, but the basic idea is: you lock your rate, and if rates fall enough before closing, you may be able to adjust lower. (American Financing)

Key point: float-downs usually come with rules (timing windows, minimum drops, fees). Don’t assume it’s automatic—ask up front.

The Document That Tells the Truth: Your Loan Estimate

If you’re not sure whether you’re locked, don’t guess. Look at your Loan Estimate.

The CFPB says you can check near the top of page 1 to see whether your rate is locked, and until when. (Consumer Financial Protection Bureau) If your rate is locked at the time the Loan Estimate is delivered, the lock end date/time must be disclosed. (Consumer Financial Protection Bureau)

Translation: you should know your lock expiration date like you know your closing date.

Common Mistakes Move-Up Buyers Make (And What To Do Instead)

Here’s where people get into trouble—especially with floating.

1) Floating with no “stop-loss” plan (the #1 mistake)

Why it’s a problem: Floating feels fine… until rates bump up and your payment bumps up. For move-up buyers, that can reduce your buying power or push your payment past your comfort zone after you’ve already committed to a new home.

Do this instead: Set a clear lock trigger before you float. For example:

• “If we can lock at 6.00% or better, we lock immediately.”
• “If rates rise to 6.50%, we lock to stop the damage.”
  This is your guardrail. Floating without guardrails is like driving 1604 with your eyes half closed. Technically possible. Not recommended.

2) Floating while your sale timeline is still shaky

Why it’s a problem: If your current home isn’t under contract yet—or the buyer is still negotiating repairs, appraisal, or financing—your purchase timeline can slide. Then you’re forced to lock at the last minute, often at the worst time.

Do this instead: If your sale isn’t firm, choose one:

• Lock once your sale is under contract and past inspections, or
• Choose a longer lock, or
• Lock with a float-down option (if available) so you’re protected. (Zillow)

3) Thinking floating is “free”

Why it’s a problem: A higher rate can quietly change your whole plan:

• Higher payment
• Lower max purchase price
• Tougher debt-to-income ratios
• Less room for repairs, moving costs, or upgrades

Do this instead: Ask your lender for payments at three rate points:

• Today’s rate
• +0.25%
• +0.50%
  Then decide: “If rates hit that higher number, am I still happy buying this home?” If not, lock sooner.

4) Locking too short because it sounds cheaper

Why it’s a problem: A short lock can backfire if anything delays closing. Extensions may cost money, and move-up buyers are more likely to see date shifts because you’re coordinating two transactions.

Do this instead: Lock for your real timeline, not your best-case timeline. Zillow notes common lock periods are 30/45/60 days—pick the one that actually fits your closing plan. (Zillow)

5) Waiting to ask about float-downs until after you lock

Why it’s a problem: Many buyers assume they can “just get the lower rate” if rates drop. Usually, that’s not how it works.

Do this instead: Ask early:

• Do you offer a float-down?
• What drop is required?
• Any fee?
• How close to closing can it be used? (American Financing)

6) Letting headlines run your decision

Why it’s a problem: Rates can move fast, and forecasting is not a strategy. Even recent reporting suggests rates could dip in 2026, but timing windows may be brief and uncertain. (Investopedia)

Do this instead: Use a simple plan: protect your budget first (lock), then look for upside (float-down or clear triggers).

A Simple “Floating Plan Template” You Can Use Today

If you want to float, do it with structure. Here’s a template you can copy/paste and use with your lender:

1. My target rate to lock: ________
2. My max rate before we lock (stop-loss): ________
3. My expected closing date: ________
4. My lock length needed: ________ days
5. Float-down available? Yes / No (rules: ________)

That’s it. Now you’re not winging it.

How I Help You Keep This From Turning Into a Stress Fest

Move-up buying isn’t just “find a house.” It’s timing, negotiation, and making sure your financing strategy matches real life.

I help you:

• Set a sell-to-buy timeline that makes sense in today’s market
• Line up closing dates and possession terms to reduce risk
• Avoid floating blindly (and avoid locking too short)
• Coordinate with your lender so your rate strategy fits your contract strategy

If you want to talk through your numbers and timing, reach out.

Mark Stillings, Associate Broker, M.B.A
210.772.3123