Michael Greenberger is one of my lights into these types of issues. He is a nice remedy to the mistaken theories of many, including alas Paul Krugman, who does not believe that speculators can influence prices, even in the short term. But there are far, far worse, who know better but sell themselves for pay.
Greenberger highlights the speculative pools activity of Goldman Sachs and Morgan Stanley. But there are far worse excesses being done by other actors through their own trading desks, among these JPM and HSBC it appears at least from government records, in the derivatives markets.
Anyone who watches the markets closely knows full well how derivatives and leverage can be used to manipulate the physical markets with paper in a fiat regime, especially where the "delivery" of goods can be financialized, leveraged, and nakedly shorted, behind the cover of opaqueness and complexity.
Thus the use of such financial tools allows some participants to essentially defer the equilibrium of supply and demand for unusually long periods of time, until some event or accident triggers an exposure, a sudden reckoning, and a subsequent collapse.
I think the extreme fractional reserve nature of the current metals markets is an accident waiting to happen, awaiting only the right mix of margin calls and short term demand. And then everyone will be surprised that such a grand theft went on for so many years, unnoticed, except that is by a stalwart few, much in the manner of the Madoff fund and Harry Markopolos.
The remedy for much that is wrong in the markets today can be remedied by transparency and limitations on things like positions, and a return to laws passed after the last financial crisis of this magnitude that had served the nation well for over sixty years.
