Earlier quoted context omitted.
I tried for a while to push internally and amongst a few of the markets to move to ISIN, Currency, MIC but yeah…anything but that. Honestly the problem is the ticker is too valuable advertising for the listed company, and since listings are not governed by a central regulator in the same way they are in Europe, for example, there’s always going to be this sort of friction about who is willing to bend the most to win…
I think ISINs being used in Europe might even predate the EU taking charge of a lot of financial market regulation. Probably they became more popular/important specifically because tickers did not, which in turn is probably because there are so many countries/exchanges that a global exchange-driven namespace was never really feasible?
Easier, if somewhat more verbose, to use the three in combo to identify. Helped somewhat by the message volumes being a small fraction of what they are in the US. Less need to optimize on a per order, or per market data packet basis.
Also explains why FIX is more prevalent in EU markets than it is in the US.