When moving into a German rental flat you need money at the same time for the move, furnishing and the security deposit. A offered rental deposit guarantee (Mietkautionsbürgschaft) can therefore seem attractive: instead of providing a cash deposit immediately, another party is supposed to stand in for the landlord. To make a good decision you must not only compare the immediate account balance. Fees, remaining liability, duration and actual release are part of it.
First clarify the concretely accepted security
Read the draft tenancy agreement and the offered deed together. Which security has been agreed and is the offered guarantee actually intended to replace it? Do not assume that the purchase of a product automatically binds the landlord to another form of security. Clarify acceptance and timing before money or deeds are handed over uncoordinatedly.
§ 551 BGB contains, for residential tenancy, in principle the upper limit of three months' rent excluding separately stated operating costs and, where a cash sum is agreed, the right to three equal monthly instalments. [MIETSICHERHEIT] The statutory instalment payment is therefore a real basis for comparison. An offer does not become necessary solely because you do not wish to provide the full cash deposit on a single day.
Differentiate between a guarantee and your own discharge from debt
§ 765 BGB describes the obligation of a guarantor towards the creditor of another person. [BUERGSCHAFT] If a product provides such security, that does not automatically mean that legitimate claims arising from your tenancy disappear economically for you.
According to § 774 paragraph 1, upon satisfaction of the creditor the claim generally passes to the guarantor; the provision contains further limits and leaves certain objections unaffected. [RUECKGRIFF] For the specific product you should therefore check which recourse claims may arise against you after a payment and how a disputed landlord claim is handled. A paid fee and any later reimbursement claim are different amounts.
Our editorial recommendation is not to read the deed only by its heading. Ask about the scope of security, conditions for enforcement, the information route in the event of a claim and your options for action. The article does not confirm any particular clause as effective and recommends no provider.
Put tied-up money and final costs side by side
A cash deposit initially ties up your liquidity, but it is not already spent as a fee. Its later settlement depends on the concrete claims. § 551 paragraph 3 regulates, for cash security in particular, separate investment and returns, with a special interest exception for certain halls of residence. [MIETSICHERHEIT]
If the concrete guarantee offer provides for ongoing charges, you record them according to its exact terms. A hypothetical comparison assumes a security deposit of 1800 euros and a purely invented annual charge of 90 euros. Over five full years of fees that would be 450 euros, without thereby building up your own 1800-euro deposit balance. The figures are not market prices; minimum charges, partial periods or price changes are not included in this simple example.
Put alongside which other costs you would actually avoid with the freed liquidity. Use documented amounts for this. A potential saving from a merely presumed overdraft interest is not yet a certain advantage. Your own reserve after the move must also remain viable.
Consider a later conversion
Perhaps you only want to bridge the initial moving-in phase and later provide a cash deposit. Clarify before signing the contract whether and how the parties accept this conversion, when the new security will be provided and what proof ends the old commitment. The mere intention to switch later is not an automatic release from an existing deed.
The same applies on moving out. End of the tenancy, return of the flat, final inspection of possible claims and release of the security are different steps. Ask in the concrete offer which event ends the obligation to pay fees and who needs to make which declaration for that. Do not plan on a free return or day-precise reimbursement unless it is appropriately confirmed.
A comparison with an intentionally open outcome
A tenant wants to keep her reserve for the move. She first places three options side by side: agreed cash deposit with permissible instalment payments, the concretely accepted substitute guarantee and another solution agreed with all parties. For each option she notes initial payments, further costs and continuing risks.
She decides on the basis of her actual assumed tenancy duration and the complete offer. The guarantee is neither blanketly devalued nor described as free insurance against her own obligations. The fair yardstick is: how much money remains available when, which costs are final and for what can I still be held liable?