Yahoo has formally notified US regulators that it is spinning off its stake in Chinese e-commerce giant Alibaba to an independent new company called Aabaco Holdings.Aabaco will wind up owning approximately 384 million shares of Alibaba Group, representing an interest of about 15%, according to a filing with the US Securities and Exchange Commission.The move was designed to sidestep taxes and appease investors eager to tap into Yahoo’s multi-billion-dollar stake in Alibaba.It is also seen as a chance for Yahoo CEO Marissa Mayer to show she can lead the company to renewed glory.