Keep in mind - which I'm sure you have - is that IVZ is NOT...

Keep in mind - which I'm sure you have - is that IVZ is NOT traded in the US on a recognised exchange, only on an OTC market (Over the Counter) whereby its "Market-maker" is an individual who buys & sells from traders prepared to do business with him/her/it. Hence the measly low turnover each day there. However if e.g. IVZ was listed on the LME (London Metals Exchange?) the trading on that Exchange would reflect a vastly different situation. From memory 88E lists there?
Meantime keep an eye on IVZOA. Some posters have recently questioned : Why buy them at say 10.0 (albeit with an intrinsic long-dated time value till 07 Jun 26 and an exercise price of 20.0 by then) when you can buy the shares @ 16 i.e not much leverage at all, and IMO there's so little liquidity in them because most of the daily trades are all being done - both ways - by only 1 trader with perhaps 2 or more accounts - shorting perhaps with #1 account (i.e. borrowing from #2 account) and then buying back at a lower price later in the day by that #2 account, but only down to a certain SP 0.1 of a cent above where there's a large buy order of his/her's sitting, of say 200,000.
He/she sold to me - on his journey South yesterday - of a much smaller trade volume - and, from memory, was the 2nd last trade of the day, at my buy price of 9.5, closing at 9.6 at 4.00pm.
Note too these Oppies, like all other listed Oppies, are only traded on the ASX, and thus not on the CBOE (formerly called the Chi-X) that uses the Exchange symbol CXA on a Course of Sale page.