[imagin8or]

Regarding limited trading: anyone but a retail trader could trade the forward OTC rather than this illiquid thing on the exchange. We can trade our guesses for tomorrow's price (which is really the live current price) as much as we want, and it will just wash out tomorrow.

Regarding length of ownership: so I make a fund which owns an LTSE-listed stock for a longer term, and people trade my fund instead.

Ultimately, neither of those things is much use, nor even necessary. A much stronger driver for long-termism would be to derive the dividend from the last 3 years of profits; since prices are estimates of future value and future dividend, the actual value of those would be smoothed; if any action can only make a small difference to the dividend, there is much less focus on quarterly results.

A formula or at least limits on dividends (no windfalls) would reduce the interest to activist investors who might see a pot of cash and seek to liberate it.