Nike NKE.N was down almost 5% after HSBC downgraded the stock to "hold". By Sinéad Carew Jan 10 (Reuters) - Wall Street's main indexes tumbled on Monday with Nasdaq leading the declines as technology stocks dropped on expectations of a sooner-than-expected rate hike that pushed U.S. Treasury yields to fresh two-year highs. Along with watching rising bond yields, investors are also anxiously awaiting this week's inflation data and what it will mean for U.S. Federal Reserve monetary policy tightening, according to Peter Tuz, president of Chase Investment Counsel in Charlottesville, Virginia.