Follow-up financing & rate lock: plan ahead

Tackling the follow-on financing only just before the fixed-rate period ends often means giving away money. A forward-looking strategy 36 to 60 months in advance pays off — especially now, when thousands of cheap legacy loans meet a much higher rate environment.

For many owners a moment worth several thousand euros edges closer sooner or later: the fixed-rate period of the mortgage expires. Anyone who financed between 2012 and 2021 sometimes paid only around one percent. In 2026 the world looks different — and the monthly load on refinancing rises noticeably for many.

The good news: this phase is not a fate you passively endure. It is a lever. Plan in time, and you can cushion the rate shock, force the bank into competition and lock in terms before they may become more expensive. This guide explains how — with concrete numbers, classic mistakes and their fixes.

What we are really talking about: three terms

Before the money, three basics that hang together:

• Fixed-rate period (Sollzinsbindung): the period in which your interest rate is fixed. 10 to 20 years is common, shorter or longer is possible.
• Residual debt: the amount still open at the end of the fixed period. Few loans are fully repaid after the first fix.
• Follow-on financing: continuing that residual debt on new terms.

Two main routes are available for follow-on financing — plus a powerful instrument for advance planning. We look at both next.

Why 2026 hits so many: the rate shock

After the sharp rate rise in 2022 and 2023 (from around one percent to about four), construction rates eased slightly in 2024 and 2025. As of spring/summer 2026, ten-year fixed terms sit roughly in the 3,5 %–4,1 % effective band — depending on creditworthiness, property and loan-to-value. ECB rate cuts support the trend, but a return to one-percent territory is not on the cards for most observers.

A typical calculation shows what that means:

Residual debt €180,000, old rate 1,3 % → payment approx. €540. New rate 4,0 % at the same repayment → payment just under €1,000. Extra load: almost €450 a month.

Such jumps are currently the rule, not the exception. That is precisely why it pays to act early — not only when the letter from the bank hits the mailbox.

Two paths: prolongation or refinancing

At the end of the fixed period, two options are principally open.

Prolongation — extend with your current bank. You continue the loan at the current lender at new rates and a new term. No bank change, just adjusted conditions. It is the most convenient path — and precisely for that reason the most common mistake. Banks know many clients avoid the effort of switching and price it in. Prolongation offers regularly sit visibly above market.

Refinancing — switch to another bank. You redeem the old loan and continue with a new provider on better terms. Here you have full access to the entire market — and thus the biggest savings potential.

	Prolongation	Refinancing
Where	current bank	new bank
Effort	minimal	low (land charge assignment)
Negotiating room	usually small	large (whole market)
Terms	rarely the cheapest	often clearly better
Extra cost	none	notary/land-register fees for assignment

Rule of thumb: a rate gap of 0,2 to 0,3 percentage points can already justify a switch — with higher residual debt even less. Always run the numbers. And even if you stay with your bank in the end: a comparable offer in hand is the strongest lever to renegotiate the prolongation.

The forward loan: lock today's rates for tomorrow

The most important instrument of forward-looking planning is the forward loan. You sign a loan contract today that only gets paid out in months or years. The bank locks in the rate at signature and guarantees it until the start date.

In concrete terms: owners whose fixed-rate period is visibly ending secure today's rate for their future follow-on financing. During the lead time neither credit nor availability interest is charged. Depending on the provider, up to 60 months lead time is possible (some banks up to 66, many cap at 36).

What it costs: the forward premium

The bank charges a premium for the rate guarantee — comparable to an insurance premium against rising rates. 0,01 to 0,03 percentage points per lead-time month is usual. Over 24 months that is roughly 0,24 to 0,72 percentage points. On a €200,000 loan the monthly payment rises by about €40 to €120. The shorter the lead time and the lower the premium, the cheaper the locked rate. With very short lead times (up to about twelve months) some banks even waive the premium entirely.

That is the core: the risk is symmetric. A forward loan makes sense if you expect rising rates and value planning certainty. If you expect rates to fall, you are usually better off waiting until close to the end of the fix. The rate forecast is the decisive input — and nobody knows it for certain.

Your statutory ace: § 489 BGB

Many owners do not know they hold a strong right. Under § 489 BGB, you may terminate any real-estate loan ten years after full disbursement with six months' notice — and without a prepayment penalty. That applies even if you originally agreed a 15- or 20-year fix.

This opens a smart strategy: pick a long fix in a low-rate phase, secure the low level long-term — and still exit via § 489 BGB after ten years if rates have fallen by then.

The same mistakes crop up around this special termination right:

• Wrong start date: the ten years run from full disbursement, not from signature.
• Missed notice: the six-month period is overlooked.
• No follow-on ready: whoever terminates without lining up new financing in parallel risks ending up without one.

Tip: already after six to seven years from disbursement, check whether the special termination right could become interesting for you.

What a bank switch really costs

A stubborn myth keeps many from switching: it supposedly costs thousands of euros. In reality, only notary and land-register fees apply to transfer the land charge — and they are manageable.

The key term is the land-charge assignment: the old bank simply transfers the existing land charge to the new bank. Because the land charge is legally "abstract", no new charge needs to be created — the notary only certifies the signature. That is significantly cheaper than deleting the old land charge and registering a new one.

As a rough guide, sources cite values between about 0,2 % and 0,5 % of the residual debt for notary and land register together. On €200,000 that is about €400 to €1,000. The point: if the new bank offers a rate advantage of about 0,5 %, that equals about €1,000 saved per year on this residual debt — the switching cost is often earned back within six to twelve months.

Still, do the maths: if the rate benefit is only 0,1 percentage points, the effort barely pays. The rate saving should clearly outweigh the assignment cost.

The timeline: when to do what

Planning ahead does not mean acting frantically — but in the right order.

• 36 to 60 months before — set the strategy. Watch rate developments, calculate the expected residual debt, and think about whether a forward loan matches your risk appetite. The fundamental choice happens here: lock in or preserve flexibility.
• 12 to 36 months before — compare concretely and, if needed, lock. The classic forward-loan window. Obtain three to five offers from different banks and, if desired, lock the current level.
• Around 12 months before — transition without premium. Anyone unwilling to pay a forward premium can align the old and new loans about twelve months before expiry so that neither premium nor availability interest applies.
• At the latest 3 to 6 months before — everything wrapped up. The bank often sends the prolongation offer only about three months before expiry — far too late for a proper comparison.

The thread: the earlier you know the market, the stronger your position.

Typical problems — and how to solve them

1. Too late. Many only act when the bank's prolongation offer arrives. Then there is no time for a real market comparison or a forward loan. Fix: set a reminder 36 months before expiry — and put the end date firmly in the calendar.

2. The convenience trap. Signing the house bank's offer feels easy. Prolongation terms are often above market, which over ten years quickly amounts to four- to five-figure extra costs. Fix: force competition. An independent comparison costs nothing and delivers either a better offer or a strong argument in negotiation.

3. The rate shock. Jumping from around 1 % to 4 % can nearly double the payment. Fix: plan early, check the forward loan — and channel savings into special repayments before the new, higher rate kicks in. Every euro less of residual debt lowers the future load.

4. § 489 BGB mistakes. Wrong start date, missed notice, no follow-on plan. Fix: count ten years from full disbursement, respect the six-month notice period and apply for the new financing alongside the termination.

5. Unnecessary new land-charge registration. Deleting the old land charge and registering a new one costs extra. Fix: insist on the land-charge assignment — the cheaper and faster path.

6. Underestimating the forward risk. Locking early while expecting falling rates can mean paying a high premium for a rate that later would have been cheaper. Fix: weigh the premium against the expected rise. With a clear expectation of falling rates, wait; with uncertainty and a long lead time, accept the premium as a conscious price for planning certainty.

7. The "rate gap". If the old loan ends before the new one starts, a gap and stress loom. Fix: coordinate the transition so that the new bank redeems exactly on the end date — seamless, without double loads.

Practical tips at a glance

• Start early: strategy 36–60 months before, concrete comparison 12–36 months before.
• Never renew blindly: the prolongation offer is a starting point for negotiation, not a finished contract.
• Get multiple offers: compare three to five banks — easiest via an independent broker with access to hundreds of providers.
• Reduce the residual debt: use special repayments while the old cheap rate still runs.
• Check the forward loan: useful when expecting rising rates and wanting planning certainty.
• Know § 489 BGB: exit after 10 years from disbursement, 6 months' notice, no prepayment penalty.
• Read switching costs correctly: land-charge assignment, not new registration — usually earned back in under a year.
• Secure a seamless transition: no rate gap between the old and new loan.

Conclusion

Follow-on financing is not a necessary evil but a real chance to make your finances weather-proof for the next decade. In 2026 in particular — when many cheap legacy loans meet a much higher rate level — preparation decides over several thousand euros. Anyone who sets the strategy 36 to 60 months ahead, compares early, knows the forward loan and the § 489 BGB right, and reads the real switching costs realistically, negotiates from a position of strength — instead of being driven by the letter from the house bank.

Note: this article is general information and does not replace individual financing or tax advice. Rates, premiums and terms depend on property and creditworthiness, change continuously and can vary regionally. For a robust offer and a strategy tailored to your situation, consult an independent financing expert.