So, anyone actually got a proper brokerage account?

Something with a nice, deep, access to the US markets? Like OTC?

What I want to see is the spread (so, the difference between buy and sell, or bid and offer) and also, if it’s indicated, size, for AMGDF and ARGGY.

At some level of theory they should be the same price. But one is the London stock (AML) traded OTC in the US. The other is an unsponsored ADR traded in the US. There are two – at least – possible reasons for price differences. The most obvious being that one isn’t fully fungible, or only at cost, into the other. The other is that the spread on one of them is so wide that they are in fact pretty much the same price, it’s the mid points being quoted which differ.

So, if Schwab or whoever actually allow OTC trading, perhaps it would be possible to have a look?

What is the bid offer on AMGDF and ARGGY?

This is just pulling on a thread. Those prices should be the same. They don’t appear to be, so why aren’t they? One answer, as above, is that they are. Another is that they do differ but trade is only possible in such small size that no one bothers to arbitrage. But whatever the answer it would be nice to know. Either, there’s an inefficiency that can be traded, or there’s an inefficiency which says that the price difference cannot be traded. Either answer would bolster Ricardo – things should be the same price accounting for transport costs – but which is it?