SAN JOSE, Calif. (AP) — Polycom Inc., which makes videoconferencing equipment, said Wednesday that its board of directors approved a $400 million buyback of its shares. That would be about enough to buy 20 percent of the company's outstanding 169.6 million shares at recent prices. The San Jose, Calif., company said that it would complete the buyback through a $250 million "Dutch auction" followed by purchases on the open market or in privately negotiated deals. Polycom will fund the program with $150 million in cash and a $250 million loan. The buyback will launch on Friday and shares will be priced between $10 per share and $11.50 per share. In a Dutch auction, shareholders can decide how many shares they want to sell and at what price, within a specified range.