Swiss pharmaceutical group Roche says it is offering $43.7 billion (SFr44.7 billion) to take over the remaining shares of Genentech.
Roche, which already owns 55.9 per cent of the San Francisco-based drug maker, said on Monday it was offering $89 per share, 8.8 per cent above the closing price on Friday and 19 per cent above the price a month ago.
"The combined entity will be the seventh-largest US pharmaceuticals company in terms of market share," Roche said in a statement.
The total offer is the largest ever made by a Swiss concern for a takeover.
Roche has been a partner with Genentech since 1990.
Also on Monday Roche revealed that its profit for the first half of the year had dropped by two per cent to SFr5.732 billion. Turnover fell by four per cent to SFr22.004 billion.
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