The sell off is only a part of overall stake in the company and might be just because he needs some readies to pay for all his Christmas card list. He has done it so as not to harm SAP's stock price. To protect the stock price, a bank will place 10 million euros worth of the shares every month until no more are left.
The sell off will happen between January through November next year , SAP said in a regulatory statement. SAP had been gaining slightly, but lost 0.5 percent on the news. Plattner is SAP's largest shareholder with 121.49 million shares, representing a 9.89 percent stake. Based on the current share price the stake is worth a little over 7 billion euros.