Goldman Sachs-backed and US-based file sharing company Dropbox has bought tablet advertising company TapEngage for an undisclosed sum.
In March Dropbox bought Cove, an organisational collaboration startup founded by three ex-Facebook engineers, for an undisclosed sum.
The move follows a $250m series B round closed by Dropbox in October featuring financial services firm Goldman Sachs and several VC investors.
The US-based bank was joined by venture firm Index Ventures, which led the round, as well as venture and private equity firms Benchmark Capital, Greylock Partners, Institutional Venture Partners, RIT Capital Partners and Valiant Capital Partners. The latest round values Dropbox at $4bn, according to UK news provider Financial Times.
Sequoia Capital, Accel Partners, Hadi and Ali Partovi also joined the round, taking the total venture funding raised by Dropbox since inception to $257.2m.