Roche offers to buy out Genentech for $43.7 billion Monday July 21, 12:59 am ET BASEL, Switzerland (Reuters) - Swiss drugmaker Roche Holding AG (VTX:ROG.VX - News) made an offer to acquire all outstanding shares in its U.S. partner Genentech Inc (NYSENA - News) for $43.7 billion. Roche, which already owns 55.9 percent of Genentech, said on Monday it would offer $89 per share to buy up the remaining stake, a 9 percent premium to the biotech company's closing share price on Friday. Roche expects the combination to generate annual pre-tax cost synergies of about $750-$850 million and to be accretive to earnings per share in the first year after closing. The deal will have no impact on Roche's 2008 sales and earnings per share forecast or dividend policy.