Seems pretty simple to me, and I'd take this as bearish for Silver.
Pool accounts are highly liquid, with a small spread. The premium is as low as you can get outside of futures. Holders of pool accounts can liquidate funds at the first sign of weakness and have a buyer ready and waiting.
On the other hand bullion coins are not nearly as liquid, they have a large buy and sell spread. The premium on Perth bullion is easily 10% higher than spot in a lot of cases, or more. Holders of physical bullion can not liquidate easily and must find a buyer first.
So if you were running a business, which is the obvious path to take to minimize your risk in the face of a massive price drop? Would you want to be the CFO who is obligated to buy back large quantities of certificates and be left holding bullion? Or would you rather convert that bullion into coins, minimize your liabilities, AND making greater profits on the initial sale as an added bonus?
The conspiracy crowd completely dismisses the fact that these guys have a business to run.
Peak Oil - Coming soon to everything near you