The NYSE has released new data for margin debt, now available through March. I've updated the charts in this commentary to include the latest numbers.
http://www.advisorperspectives.com/dshort/updates/NYSE-Margin-Debt-and-the-SPX.php
http://www.advisorperspectives.com/dshort/updates/NYSE-Margin-Debt-and-the-SPX.php