In recent years, bloggers, traders, and other market participants have made repeated accusations about manipulative trading practices by JP Morgan (NYSE:

) in the precious metals futures markets.The persistent rumors and allegations have resulted in an

by the Commodities Futures Trading Commission (CFTC) into the firm's practices. JP Morgan is one of the largest participants in the gold and silver futures markets in the world. In particular, its activity in the much smaller silver market has come under scrutiny. On Thursday, Blythe Masters, the head of JP Morgan's commodities business,

and refuted the allegations of manipulative trading. She also asserted that the firm does not make proprietary directional bets on precious metals prices. Rather, all of JP Morgan's activity is related to its client business, according to Masters. Here are some of the highlights of her CNBC interview.

Financial blog ZeroHedge, which has been one of the loudest and most aggressive critics of JP Morgan's trading activity in precious metals,

. Simply put, the numbers don't add up. In 2011, JP Morgan ranked first on Wall Street in commodities revenue. In fact, its trading revenues tripled to $2.8 billion. ZeroHedge argues that it is very difficult to comprehend how the group's revenues could have

without the firm making proprietary market bets with its own money.

"Taken at face value, it would mean that all else being equal, JPMorgan transacted at least 3 times more in flow in 2011 than in 2010. Yet, everyone knows that trading volumes in 2011 slumped relative to 2010. So no, Blythe, we appreciate your explanation, but we would appreciate the truth even more."