I have searched around and have not found anything conclusive or obvious about condition 12 and condition 78 that you will see on time and sales for equities. Condition 78 is listed on maybe 50% of trades so is probably something very common and simple. Condition 12 much less so, and seems to be listed on prints that go off way outside the market. On a side note, many of these Condition 12 trades are reported via ADFN on my time and sales. Maybe they're just late. I see quite a few interesting things reported from ADFN. I found this on the net on modifiers for T&S, but I'm not sure which ones correlate to my condition numbers: A - Depth on Ask side B - Depth on Bid side F - Fast trading H - Depth on Bid and Ask I - Order imbalance L - Closed quote N - Non-firm quote O - Opening quote R - Regular, two-sided open quote S - Regular, one-sided open quote Y- Regular, one-sided open quote X - Order influx Z â No Open/No Resume Null - if no value provided Any info or link to where these are summed up would be appreciated, thanks.