Fixed vs. Mixed-Rate Mortgage in Mexico: Which Is Better?

Choosing between a fixed-rate and a mixed-rate mortgage is one of the decisions that most affects the total cost of a 15- or 20-year home loan. With a fixed rate, the interest stays the same for the entire life of the loan, so your monthly payment never changes. With a mixed rate, you start with a fixed rate for an initial period, and then the loan switches to a variable rate tied to a benchmark indicator. There is no single right answer: it depends on your risk tolerance, your repayment horizon, and how likely you think rates are to fall or rise in the coming years.

How each type works

A fixed-rate mortgage sets an interest percentage when the contract is signed, and that number never moves, no matter what happens with the country's economic conditions. Your monthly principal-and-interest payment stays stable, which makes it easier to plan a household budget over the long term. A mixed-rate mortgage, by contrast, combines two stages: an initial period with a fixed rate (usually covering roughly the first few years of the loan) and a second stage in which the rate adjusts periodically according to a market benchmark index plus a margin set by the bank. During the fixed stage your payment is predictable; once the variable stage begins, your monthly payment can go up or down depending on how that indicator moves. Some banks offer mixed-rate loans with adjustment caps, which limit how much the rate can rise at each review, although not all institutions include this protection by default.

Advantages and risks of each option

A fixed rate offers total certainty: you know exactly how much you will pay each month until the loan is paid off, which is valuable if your income is stable but tight. The flip side is that it usually starts at a somewhat higher entry rate than the initial stage of a mixed-rate loan, as compensation for the bank taking on the risk. A mixed rate usually starts with a more attractive entry rate, which lowers the monthly payment in the first few years, but it shifts the risk of market fluctuations onto the borrower once the fixed period ends.

• Fixed rate: constant payment, easy to budget, protects against future rate increases.
• Fixed rate: at some banks it may require a larger down payment or a stronger credit profile.
• Mixed rate: lower initial monthly payment, useful if you expect your income to grow.
• Mixed rate: exposes the buyer to increases if the benchmark indicator rises.
• Both: check whether there is a penalty for early repayment or for mortgage substitution (sustitución hipotecaria, i.e., moving the loan to another bank).
• Both: compare the CAT (Costo Anual Total, or Total Annual Cost) and not just the nominal rate.

Which type of buyer each one suits

If you value certainty over potential savings, or if your household budget is tight and cannot absorb a higher monthly payment, a fixed rate is usually the safer choice. It is also a good fit for long-term loans, where market movements over 15 or 20 years are harder to predict. A mixed rate can suit buyers whose income is variable but trending upward, who want to take advantage of a lower monthly payment in the early years and plan to pay off or refinance the loan before the fixed stage ends. It is also an option to consider if you plan to sell the property or do a mortgage substitution (sustitución hipotecaria) within that initial period.

Frequently asked questions

Can I switch from a mixed rate to a fixed rate after signing?

It depends on the bank and the contract. Some institutions allow you to switch plans through a restructuring or a mortgage substitution (sustitución hipotecaria), generally for a fee. Review the specific terms of your contract before signing.

Does a mixed rate always end up costing more?

Not necessarily. If the benchmark indicator stays stable or falls, the mixed rate can end up cheaper in total paid. The risk is that it rises, which is why it pays to compare scenarios before deciding.

What should I ask the bank for in order to compare both options?

Ask for the full amortization table for each plan, the CAT for each one and, for the mixed rate, the benchmark indicator used and the maximum adjustment cap if there is one, so you can gauge the worst-case scenario.