Bulgaria has opened a tender for granting a 35-year concession on Sofia International Airport.

The future concessionaire will be required to pay a one-off concession fee of at least BGN 550 M (EUR 281 M), VAT excluded, plus an annual fee of at least BGN 9.96 M for the term of the concession.

The concessionaire will also be obliged to invest at least BGN 306.5 M during the term of the concession in the construction of a new Terminal 1 with capacity to handle three million passengers a year as well as in other elements of the airport’s infrastructure, the Transport Ministry in Sofia said in a statement on Friday.

Operators of at least one international airport generating passenger traffic of more than six million peope per year will be considered eligible bidders. They will be also required to have qualified technical staff as well as the necessary equipment. The bidders will also have to provide reliable guarantees of being able to secure financing for the project.

The concession fee (the one-off payment plus the annual payments) will carry a total of 55 points in the overall ranking of the submitted bids.

A business proposal for the operation of the airport for the term of the concession, including a social programme, will carry 25 points, investment commitments – 15 points, and measures for boosting security at the airport – 5 points.

The deadline for submitting bids will expire on 20 October 2016. The bids will be opened on the following day.

Bulgaria hopes to earn over BGN 1.2 B net for the term of the concession, according to the statement.

Several foreign-based companies have previously expressed interest in the concession, including Munich Airport, Spain’s Ferrovial and an unnamed South Korean company, according to Bulgarian media reports.

Sofia Airport has reported a 13% annual increase in passenger numbers for April. There was an increase of 14.7% in the number of passengers on scheduled international flights who form 96% of total passenger throughput. Passengers on domestic flights increased by 7.7% year-on-year in April.