Depends on your perspective... Your clearing firm may be a member of the nyse, thus follow the rules of the NYSE no mater where the execution comes from. (same goes for Amex) Execution.. I believe the ecn's and nasdaq follow the bid test rule, for listed equities that are not regulation sho pilot stocks.
1. Stocks on the Reg SHO "A" list can be shorted at any price, any time, on ARCA, INET, BRUT. 2. Stocks on the "B" list can be shorted at any price on ARCA, INET, and probably BRUT, from 16:15 to 20:00 ET. 2a. For stocks on the "B" list, from 07:00 to 09:30 ET and 16:00 to 16:15 ET: On ARCA or BRUT, the price must satisfy the tick-test based on the last trade on ARCA (and maybe INET) or BRUT, respectively. On INET, the price must satisfy the tick-test based on the previous NYSE close. 3. For stocks not on the "A" or "B" list, rule 2a applies from 07:00 to 09:30 ET and 16:00 to 20:00 ET. I don't know what happens before 07:00 on ARCA, but I expect it's the same as after 07:00. Note that you will see BRUT display offers that are below the necessary tick-test price, but you cannot take those offers. For example, if the last trade was 15.00 - an up-tick, and BRUT is displaying an offer of 14.95, and you send a buy order to BRUT at 14.97, you will see a crossed quote from BRUT. Only if you price your order at 15.00 or above will you get executed (at 15.00). It's ridiculous that, especially now that Naz owns them, they refuse to fix this