Microsoft co-founder to open investment office

• Paul Allen to open tech-focused office in Palo Alto
• To look at early stage software, Internet, tech companies
• Latest move in Allen's 30-year tech investment career

Paul Allen, the billionaire co-founder of Microsoft Corp , is opening an office in Silicon Valley to make new investments in emerging technology and internet companies.

The Palo Alto office, set to open in the next few weeks, will operate under the name of Vulcan Capital, the investment arm of Allen's Seattle-based Vulcan Inc, which manages his personal fortune, valued at about $15 billion.

Allen, 60, co-founded the world's largest software company with Bill Gates in 1975, but left in 1983 after a bout with cancer. The riches he amassed through his large stake in the company, plus successful investments in sports and real estate, have made him the world's 53rd richest person, according to Forbes magazine.

A pioneer in the early development of PC software and Microsoft's technical leader for its first eight years, Allen has been a prolific tech investor since the mid 1980s, starting several companies and founding a tech incubator called Interval Research.

He has put money into hundreds of enterprises in the past 30 years, including large stakes in AOL, Ticketmaster, film studio DreamWorks SKG and cable firm Charter Communications . His record has been checkered, making money on AOL and DreamWorks SKG, but losing billions of dollars on the bankruptcy of Charter.

Newer tech investments include online real-estate agent Redfin, shopping adviser Decide.com and smartphone audio software maker Audience Inc.

The new office in Palo Alto will focus on emerging internet, software and technology companies, including middle and late-stage venture capital and pre-IPO deals, Paul Ghaffari, Vulcan Capital's chief investment officer, told Reuters.

"We are going to expand our footprint in broad tech investments, we'd like to get more resources, people on the ground there (Silicon Valley)," said Ghaffari. "We have a real appetite to put new ideas in the portfolio."

The leader of Palo Alto office is expected to be announced in the next few days.

The arrival of Allen's empire in Silicon Valley may not be immediately popular with the biggest local companies.

The now-defunct Interval Research filed a lawsuit in 2010 against Valley stalwarts Apple Inc, Google Inc , Facebook Inc and others, claiming they stole its inventions, 300 of which are patented. The case is proceeding slowly in the courts.