Boulder-based bandwidth provider Zayo Group has filed for an IPO, saying in its S-1 filing that it is looking to raise up to $100M in a public offering. The IPO is being underwritten by Morgan Stanley, Barclays, Goldman, Sachs & Co., RBC Capital Markets, Citigroup, SunTrust Robinson Humphrey, Cowen and Company, D.A. Davidson & Co., Oppenheimer & Co., Raymond James, Stephens Inc., Wells Fargo Securities, and William Blair. Zayo is backed by Battery Ventures, Charlesbank Capital Partners, Columbia Capital, GTCR, M/C Partners, Oak Investment Partners, and others. The company reported a net loss of $137.2M on revenues of $1.0004 billion for the year ended June 30, 2013.