Facebook has raised $1.5 billion from investors, under terms which the world's No. 1 online social network says gives it a value of about $50 billion.

The company, founded in 2004, said it would begin to file public financial reports no later than April 30, 2012, which many see as a precursor to an initial public offering. It could be one of the largest IPOs ever in the technology sector.

The new funding was handled by investment bank Goldman Sachs, which raised $1 billion from non-U.S. investors in a fund that Facebook said was oversubscribed.

In December, Russian investment firm Digital Sky Technologies, Goldman Sachs and some funds managed by Goldman invested $500 million in Facebook.

(Reporting by Bill Rigby; Editing by Bernard Orr)