Manchester Airports Group (MAG) said on Monday that it is planning to participate in the Bulgarian government tender for awarding a 35-year concession contract for the operation of Sofia International Airport. MAG will provide further details at a news conference in Sofia on October 3, it said. Manchester Airports Group operates three airports in Great Britain - Manchester, London Stansted and East Midlands. The combined annual passenger traffic of the three airports totals nearly 60 million. The estimated value of the concession contract is 3.9 billion euro ($4.5 billion), Bulgaria's transport ministry said in August, when the tender was launched. The deadline for submitting offers in the tender is October 12.($ = 0.8623 euro)