Atlas Venture announced on Thursday that it raised a $950 million venture fund. Atlas Venture VI will provide early rounds of financing to young technology companies in the United States and Europe. Atlas focuses on communications, information technology and life sciences companies. In addition to the nearly $1 billion fund, the Boston-based company is raising a parallel fund for entrepreneurs and individual members of Atlas' portfolio companies, allowing them to invest in the same companies as Atlas Venture VI investors. An Atlas spokeswoman said 95 percent of their previous investors have returned to participate in the latest fund. Last year, 14 companies in Atlas' portfolio launched an IPO on either domestic or international exchanges and 11 companies were acquired.