Roll over chart to see data. Drag chart left/right to move forward/backward in time.

Weekly program trading activity conducted exclusively for member firms’ own accounts. Top chart is total principal program volume (in millions), bottom chart is the percentage of total program volume attributable to principal trading. In general, heavy program activity is bullish while light activity can be a red flag. Historically, when the percentage of total program volume is over 40% it reflects unusually heavy activity. Beginning in mid-2009, the NYSE changed the methodology for calculating this statistic, and according to the exchange the new readings are not comparable to pre-2009 statistics.