Salesforce's venture arm had also invested previously in Dropbox's Series C funding round, data provided by Crunchbase show. Dropbox, the provider of a cloud-based platform that enables users to store and share content, said in a new S-1 filing that it plans to sell 36 million Class A shares at $16 to $18 apiece. The company is issuing 27 million shares, while current investors, including co-founders Drew Houston and Arash Ferdowsi, are selling 9 million shares. At the midpoint of the range, Dropbox's IPO would be $612 million, the largest tech offering since Snap SNAP went public a year ago. Class A shares will represent 2 percent of the voting power, while Class B shares — held by Houston and Ferdowsi as well as Sequoia Capital and T. Rowe Price TROW — will account for 98 percent. Each Class B share represents 10 votes.