You're missing my point. The .PK designator is just used by a few sites, it's not an official anything. It's not used by the SEC, FINRA, MM's, it's not even used by IHUB's quote service.
The only stock site I ever go to that uses it is Yahoo and they use it for both Pinks and Greys making it of not much use.
The rest of the sites and brokers I use, don't use any identifiers for the various markets or tiers except for MyTrack which uses -V for the TSX Venture and -T for the TSX.
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