The rising level of debt is seen as a measure of investor confidence, as investors are more willing to take out debt against investments when shares are rising and they have more value in their portfolios to borrow against. The latest rise has been fueled by low interest rates and a 15% year-to-date stock-market rally.
The first time in recent decades that total margin debt exceeded 2.25 percent of G.D.P. came at the end of 1999, amid the technology stock bubble. Margin debt fell after that bubble burst, but began to rise again during the housing boom — when anecdotal evidence said some investors were using their investments to secure loans that went for down payments on homes. That boom in margin loans also ended badly.
If anything has changed yet in 2013, we certainly do not see it. Despite the early post-fiscal cliff rally, this is the same beast we rode to the 2007 highs for the Dow Industrials. The U.S. stock market is over leveraged, overpriced and has been commandeered by mechanical forces to such an extent that all holding periods are now affected by more risk than at any time in history.