Investors are running out of money - and that's bad news for stocks

Business Insider CEO Henry Blodget breaks down a recent concern being voiced by some strategists on Wall Street, which is that investor cash levels are too low. He notes that previous lows like this have sometimes correlated with a peak in the market, but that Goldman Sachs says that cash holdings are totally normal.

Executive editor Sara Silverstein says that she believes Goldman, and that other firms are making the mistake of focusing on private holdings. She argues that people might be putting cash to work in low-risk investments, just so they don't have to pay to hold cash anymore. Blodget suggests that this could suggest the overexuberance often seen at markets tops, which Silverstein doesn't buy.