Fianza vs. Bank Guarantee (Aval Bancario): What's the Difference?
These two terms get used almost interchangeably in everyday conversation about renting in Spain, but they're legally distinct — and the difference matters if you're a landlord deciding what to ask for, or a tenant deciding what's reasonable to hand over.
Fianza: the mandatory cash deposit
Under Article 36 of the LAU (Ley de Arrendamientos Urbanos), every housing lease requires a cash deposit — the fianza — of one month's rent for housing use, or two months' for use other than housing (e.g. a commercial let). This isn't optional or negotiable: it's a legal minimum requirement of any Spanish rental contract.
Aval bancario: an optional additional guarantee
An aval bancario is a bank guarantee the tenant arranges as an extra layer of security beyond the fianza — effectively a promise from a bank that funds will be available if the tenant defaults. Unlike the fianza, it isn't a legal requirement; it's something a landlord can ask for as additional protection, and a tenant can agree to or decline as part of negotiating the lease.
The legal limit worth knowing
The LAU places limits on additional guarantees during the first years of a housing lease — the fianza is fixed, but stacking a large additional guarantee on top of it isn't unrestricted. This is genuinely one of the more nuanced areas of rental law: whether a specific aval request is within legal limits depends on the contract type and exactly how the guarantee is structured, not a single flat rule that applies identically to every situation. If a requested guarantee looks unusually large relative to the rent, it's worth a specific legal check rather than assuming either "this is obviously fine" or "this is obviously illegal."
Which one should you ask for (or agree to)?
As a landlord: the fianza is yours to require regardless. Whether to also ask for an aval bancario is a judgment call based on the tenant's profile — a bank guarantee makes sense when there's a real reason for extra caution (e.g., a shorter income history, unusual contract terms), not as a default add-on to every lease.
As a tenant: the fianza is a given. If asked for an aval bancario in addition, it's reasonable to ask why, since it represents real cost and effort on your side (banks typically charge a fee to issue one). Neither "this must be illegal" nor "I have to agree to whatever's asked" is the right starting assumption — the specifics matter.
Quick answers
Can a landlord ask for both a fianza and an aval? Yes, both can apply to the same lease — they serve different functions (the fianza is the mandatory baseline deposit, the aval is additional security). The question is whether the combination stays within the legal limits on additional guarantees.
Does the fianza amount change based on furnished vs. unfurnished? No — the one-month (housing) / two-month (non-housing) split under Art. 36 is based on the use of the property, not its furnishing status.
Where does the fianza actually go once paid? In most autonomous communities, the fianza must be formally deposited with the relevant regional housing authority rather than simply held by the landlord — the specific mechanism varies by region, so check your community's requirement rather than assuming a single national process.
Estimate the real cost of a bank guarantee
If you're evaluating what an aval bancario would actually cost, try our bank guarantee calculator — it factors in the opportunity cost of tying up the guarantee amount, not just the bank's fee.
This article offers general, educational information and does not constitute tax, legal, or financial advice. Consult a qualified professional for guidance specific to your contract.