Shares of Apple Inc, the largest U.S. company by market value, are set to finish the year in the red on notable weakness for a stock that had largely been impervious to pain for several years. * Apple Inc shares are on track to finish the year down 4 percent, its first down year since 2008. * Declines this year have wiped out about $57 billion in Apple’s market capitalization, about as much as fellow Dow component DuPont Co is worth.