The claim isn't about possible workarounds, which I'm sure are almost limitless, but about a generic requirement for owners to hold stock.

What long term effect does such a requirement have, if abundant workarounds exist? Shouldn't regulation aim to solve the root cause of the problem permanently? I'm suggesting workarounds precisely because I do not see how these ideas solve anything at all.

I'm sure this is true, but you're thinking like a market person who makes a living out of doing tricks like these.

Or maybe just a mathematician who doesn't mind seeing t's crossed and i's dotted once in a while :)

there's a blanket ban on all tricks - buyers must own stock, borrowing is not allowed, derivatives are only allowed for commodity deals where the buyer collects the commodity at the end of the deal - this all becomes froth and fantasy. Which is what it really is anyway.

How would you blanket ban all tricks? One man's trick is another man's legitimate insurance contract. IIRC, as long as put and call options are allowed, *any* complex claim can be replicated in principle. They represent universal building blocks for contracts. And what about middle-men? The reality of specialization in society means that you get people who don't own stock directly but act with it like they do on behalf of others. So you must allow even more tricks for this system to function.

Currently the guiding principle is that all decoupling is good by definition, because it then becomes possible to make good money out of froth and fantasy.

Yes, but remember that good money itself is fantasy. It's been so ever since governmnents went off the gold standard. There are no physical limits to the growth of the money supply. In this sense, there is no "real" economy.

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$E(X_t|F_s) = X_s,\quad t > s$