Representing what the firm claims is the largest investment in the mobile sector this year, ad network InMobi has gained a $200 million injection of funds by Japanese telecoms specialist SoftBank.

The money will be deposited via two separate $100 million strong investments – the first at some point this September, the second in April 2012 – with InMobi claiming it will be used to fund its expansion across the globe.

Spreading out with Softbank

"The size of the investment and quality of investor validate the enormous potential in mobile today and strengthen our role in helping the industry evolve," said InMobi founder and CEO Naveen Tewari.

"We have already established ourselves as a leader in mobile advertising on every continent. This is just the beginning."

Naveen stated part of the firm's planned expansion may take the form of further acquisitions, following the firm's purchase of HTML5 ad platform Sprout at the start of August.

"With a global leader like Softbank behind us, we are now well positioned to fully capitalise on the opportunity before us through substantially increased product innovation, deeper market penetration, and acquisitions across the mobile ad value chain."

Two way deal

Outside of the boost to InMobi's bank balance, the two parties are also set to work closely together in the coming years, with Softbank's portfolio of investments in Asian internet companies serving as a gateway into the market for InMobi.

On the flip side, Softbank will be able to tout InMobi's ad network to prospective partners.

"I hope the partnership with InMobi, a fast-growing startup with significant mobile expertise and an outstanding technology platform; will further accelerate the pace of development in the mobile internet space globally," added Softbank CEO and chairman Masayoshi Son.

"We believe this partnership will help Softbank become the number 1 internet company in Asia and I look forward to working with the InMobi team."

Softbank joins existing investors Kleiner Perkins Caufield & Byers and Sherpalo Ventures.

InMobi currently claims a reach of 340 million consumers, in over 165 countries, and more than 47 billion mobile ad impressions monthly.

[source: InMobi]