Looking at your list, I see at least one organisation with a decent UK/EU presence, Interactive Brokers. Interactive Brokers also have regional regulatory coverage, e.g. in the UK (they are regulated by the FCA). Not to be interpreted as a recommendation, just sayin based on a quick glance at the list you presented ....
I would be weary of exclusively US based companies such as Lightspeed. I'm not saying that they're bad (and I'm *not* picking on Lightspeed, it just happens that Robert posted !), but there would be four areas of concern :
- Lack of regional regulatory coverage (i.e. their activities don't come under the auspices of UK FCA or European equivalents).
- Lack of local presence. Do you really want the people you're dealing with to be thousands of miles away ? Do you really want to have to deal with the timezone problem, having to wait for your account manager to wake up in the morning before you can reach them ?
- The US financial authorities are a pain in the **** to deal with. There's a reason why most European financial organisations are increasingly reluctant to take on American clients, its not because of the clients, its because of all the petty bureaucracy and form-filling associated with the US financial authorities.... it takes forever to onboard a US client. And look at the way the US authorities are treating the foreign banks (Barclays etc.) compared to the US banks in relation to the whole lawsuit thing around the financial crisis.
- The unknown-unknowns associated with the incoming US president and his openly "America First" attitude, as a non-US client you may find yourself a second class citizen (or even just difficult to get a foot in the door).
Therefore, if I were in your shoes, and UK/EU based. I would seek out local financial companies to deal with, its not exactly like the region is lacking decent financial firms (especially London which is crawling with them !!).
P.S. Robert, if I am mistaken your firm does have regional regulation, please correct me and accept my apologies !