Bharti Airtel has earmarked around $5 billion as capital expenditure (capex) for financial year 2009-10. About $2.5 billion is likely to go towards expansion of mobile services and $2.5-$3 billion for the company's tower business run by Bharti Infratel (a wholly owned subsidiary) and Indus Towers, an independent tower company formed by Bharti, Vodafone and Idea to provide passive infrastructure services.