US-backed American Tower Corporation (ATC) is preparing to make an offer to buy Indian tower management firm Viom Networks, Cellular News writes without citing its source. ATC currently operates around 10,000 tower sites in India through its local unit ATC India and is reportedly looking to increase its presence in the market through the acquisition of Viom, which operates around 42,000 towers. Viom’s majority shareholders Tata and Srei Infrastructure, which hold a combined stake of 72.5% in the firm, planned to launch an initial public offering (IPO) for the infrastructure operator in 2011 although this was derailed by a shareholder dispute. The towerco’s owners hired Citi and Credit Suisse last year to assess their options for Viom and are understood to be preparing a second attempt to launch an IPO.