Ads in the Moscow metro could bring around $100 billion to the city economy after the authorities sign a deal with a new provider later this month, the Moscow government\'s head of advertising told the Rossiiskaya Gazeta daily on Thursday. A tender to find a new company to manage the lucrative advertising space until 2015 will be held on June 21, nine days before the contract of current contractor Olymp comes to an end. \"I am sure that the tender will be successful,\" advertising head Vladimir Chrenikov said. \"Seven companies have already applied to take part. Our forecasts suggest the tender could bring in at least 3 billion rubles [$106 million] in place of the current 700 million [$25 million].\" Advertising is the Russian capital\'s third biggest source of income, bringing in 2.3 billion rubles (about $82 million) in 2010. The authorities expect a rise in demand for underground advertising after legislation banning ads on scaffolding and the sides of buildings comes into force at the end of the year.