The point about the "JPM owns 150moz of silver" is that if the proponents of that actually admitted that no one can know who owns a warehouse's stocks and it is just a theory of theirs, well it just doesn't sound as good. So they make out like it is a fact.
Here is an alternative theory I just made up reversing Martin Armstrong's Buffet manipulation: JPM is massively short silver and to give the normal mainstream investors (not silverbugs) the impression there is a massive overstock of inventories, they set up a Comex warehouse (guess when they did that, yep May 2011 just as silver peaked!) and slowly encourage investors who held silver in London and elsewhere (in non-exchange vaults/locations which are not reported so the stocks are hidden) to swap it into JPM's NY warehouse in which inventories have to be reported. JPM's has went from 0moz to 150moz pretty evenly over (as John Galt's chart shows) the past 8 years and interestingly it is all eligible, that is stocks that can be traded on Comex but are not available to do so. But the fact that JPM warehouse barely has any registered stocks indicates that the people holding silver there don't trade futures. So JPM turns hidden stocks into visible stocks, giving the impression to most normal investors of oversupply and what has happened since May 2011 - price go down.
There is one problem with this strategy, that is all futures markets have to balance shorts and longs, so the silver short need sucker longs to take the other side of the trade. What to do, well one of the banksters says "don't worry, we will just put the idea out there through some of our blogger stooges who will feed it up to the big bloggers that we actually own all that silver in our warehouses and all those silverbugs will lap it up and go long futures!" They laugh bwaahahaha and twirl their moustaches.
What do you think of that moronic theory? Since it is backed up with about as much facts as the "JPM owns 150moz of silver" theory you can't disprove it.
There are plenty of good reasons to be stacking silver (and gold) as I've be writing about in ABC Bullion's weekly updates, but the JPM long silver isn't one of them.