Shareholders in business networking site LinkedIn will sell 6.7 million shares, valued at around US$500 million, in a massive bid to raise capital for development.

The sale adds to the 1.3 million shares being offered by the company itself, bringing the total to 8 million.

CEO Jeff Weiner and CFO Steven Sordello are among those selling shares, each divesting themselves of 10% of their holdings.

Private equity firm Bain Capital will sell its entire stake of 3.7 million class-B shares, picked up when it bought into the company in 2008.

The principal purpose of the offering is to increase financial flexibility, the company says in a filing with the Securities & Exchange Commission.

"We intend to use the net proceeds from the shares we are offering for working capital and general corporate purposes, including further expansion of our product development and field sales organisations, and for capital expenditures,” the filing reads.

"In addition, we may use a portion of the proceeds from this offering for strategic acquisitions of, or investments in, complementary businesses, technologies or other assets.”

LinkedIn’s share price was relatively steady on the news, holding in the mid-US$70 range.