Guide updated 11 July 2026
You have won. Now, ten days
The best bid is not yet a contract. The contracting body requires the documentation from you and you have ten working days to deliver it; if it does not arrive complete, you are understood to withdraw your bid, it passes to the next one and it can cost you 3% of the base budget.
What they ask for
What proves what you declared in the DEUC: deeds and powers of attorney, certificates of being up to date with the Agencia Tributaria and Social Security, registration in the IAE if applicable, economic and technical solvency, the resources you committed to assign and the final guarantee. If you are registered in the ROLECE, what is already on record there does not need to be provided again.
The final guarantee
Normally 5% of the final price offered, VAT excluded, deposited with the Caja General de Depósitos or the body's own fund: in cash, with a bank guarantee or with a surety insurance. Surety insurance is usually cheaper than a bank guarantee and does not use up your risk line with the bank.
The deadline
Ten working days from the day after the requirement (art. 150.2); seven in the simplified open procedure. Tax and Social Security certificates are valid for six months: have them to hand before you are proposed.
If it does not arrive
You are understood to withdraw your bid, the same documentation is requested from the next bidder in the ranking and you are required to pay 3% of the base tender budget, VAT excluded, as a penalty. It can also be a ground for a ban on contracting if there was intent, fault or negligence.
Afterwards: getting paid
With the contract signed, invoices to the Administration are submitted in Facturae through FACe, with the body's DIR3 codes; a wrongly entered code is the most common cause of rejection. AIM PAPYR creates and validates Facturae, and if you are paid late it calculates the interest and the letter to claim it.
Your deadline and your guarantee, with your dates
Frequently asked questions
Are the ten days working days or calendar days?
Working days: Saturdays, Sundays and public holidays do not count.
Can I remedy something that is missing?
Normally the body grants three working days to remedy defects in what was submitted, but not to provide something you did not have: if the solvency did not exist when the bidding deadline ended, it cannot be fixed.
How much does a surety insurance cost?
It depends on the company and the amount; as a guide, between 0.5% and 1.5% per year of the amount guaranteed.