Swiss drugmaker Roche Holding AG (ROG.VX) said Thursday it holds 93.2% of Genentech Inc. (DNA) shares following the completion of its tender offer, with 3% more guaranteed for delivery, which all but seals the takeover of the U.S. biotech.

The Basel-based company said it will merge "as soon as practical", after which the remaining shareholders will be squeezed out and Genentech shares will cease trading.

By securing over 96%, Roche has successfully leaped the most important hurdle to completing the $46.8 billion merger, Vontobel analyst Andrew Weiss wrote in a note to investors. The merger will probably be done in the second half, which means synergies will start to kick in this year.

"The most important next step is to secure the investment in Genentech and make sure that key scientists at Genentech don't jump off," Weiss said.

At 0845 GMT, Roche shares were up 0.8%, or CHF1.20, at CHF150, slightly outperforming the broader market.

Roche first launched a bid for the 44% of Genentech shares it didn't already own in July, 2008, offering $89 a share which the U.S. biotech firm snubbed as too low. After several months of gridlock, Roche tried a hostile approach with a reduced $86.50 bid.

In March, Roche lifted its takeover offer to $93 a share, followed just days later by an improved $95 a share bid, which Genentech recommended its stockholders to accept.

Roche has raised close to $40 billion on the bond market for the acquisition in recent weeks. Market interest in the rare Roche issue was enormous, lead manager UBS AG (UBS) told Dow Jones Newswires at the time.

The Swiss pharmaceutical giant first got involved with Genentech in 1990, when it took a near-60% stake in the U.S. biotech for $1.2 billion. It later bought the remaining stake, but resold a sizeable chunk of it on the open market.

Company Web Site: http://www.roche.com

-By Hans Schoemaker, Dow Jones Newswires; +41-43-4438045; hans.schoemaker@dowjones.com