The New York Stock Exchange publishes end-of-month data for margin debt on the NYXdata website, where we can also find historical data back to 1959. Let's examine the numbers and study the relationship between margin debt and the market, using the S&P 500 as the surrogate for the latter.
The Latest Margin Data
The NYSE margin debt data is about a month old when it is published. The latest debt level is up 1.2% month-over-month. Real (inflation-adjusted) debt rose 0.82% month-over-month and is 1.3% off its record high two months prior in April.
NYSE Investor Credit
Lance Roberts of STA Wealth Management analyzes margin debt in the larger context that includes free cash accounts and credit balances in margin accounts. Essentially, he calculates the Credit Balance as the sum of Free Credit Cash Accounts and Credit Balances in Margin Accounts minus Margin Debt. The chart below illustrates the mathematics of Credit Balance with an overlay of the S&P 500. Note that the chart below is based on nominal data, not adjusted for inflation.