can dark pools distinguish between a sell order to close, or a short order to open?

[Robert Morse]

No.

Sorry, I meant the trade prints from all exchanges. Do they indicate which trades had a short sell when matched?

 

[qlai]

For US equities, no. Brokers are doing the checks, as Robert mentioned, but exchanges just see buy or sell orders. Legit dark pools should not be getting such info either.