There's Only One Buyer Keeping S&P 500's Bull Market Alive

"Corporate buybacks are the sole demand for corporate equities in this market," David Kostin, the chief U.S. equity strategist at Goldman Sachs Group Inc., said in a Feb. 23 Bloomberg Television interview. "It's been a very challenging market this year in terms of some of the macro rotations, concerns about China and oil, which have encouraged fund managers to reduce their exposure."