Margin Debt Gained Quickly. It's Now At a Record $1.2 Trillion.The Dow Falls For Third Straight SessionLast Updated:4 hours agoMargin debt has soared at an eye-watering pace.The rise in margin debt—effectively a loan taken out by an investor from a broker to buy stocks—in the six months through October is the second largest gain since the six months through March 2000, which was almost a quarter of a century ago, according to Deutsche Bank. It stands at a new all-time high of $1.18 trillion.Investors’ use of margin tends to parallel moves in stock markets. Margin debt balances balloon when investors chase momentum, buying at high prices with hopes to sell at even higher levels.