Yahoo said Tuesday the U.S. Internal Revenue Service (IRS) had denied the company’s request for a private letter ruling on whether the spinoff of its stake in the Chinese e-commerce giant would be considered tax free. Yahoo’s shares fell as much as 15.8 percent after the announcement but they pared their losses later in extended trading and were down about 3 percent. Despite the IRS denial of the letter, Yahoo said the IRS had not concluded the transaction would be taxable.