* JPMorgan remains a defendant
* Investors say silver prices driven down illegally
* HSBC entered "tolling agreement"
By Jonathan Stempel
NEW YORK, Sept 14 (Reuters) - HSBC Holdings Plc (HSBA.L) has for now been dropped from an investor lawsuit accusing it of conspiring to drive down silver prices, leaving JPMorgan Chase & Co (JPM.N) as the only bank defendant in the case.
Investors had in at least 43 complaints filed in 2010 and 2011 accused banks of amassing hundreds of millions of dollars in illegal profit by manipulating prices of COMEX silver futures and options contracts, including by amassing huge short positions.
While these lawsuits were later combined, an amended complaint filed on Wednesday in the U.S. District Court in Manhattan dropped HSBC as a defendant, saying the bank had entered a "tolling agreement" with the plaintiffs.
Such agreements may give plaintiffs more time to raise claims without tripping rules on statutes of limitations, or indicate that settlement talks are ongoing. The complaint does not explain why HSBC entered its tolling agreement.
HSBC spokesman Rob Sherman declined to comment on the tolling agreement, but said "we will continue to vigorously defend ourselves through the proper legal channels." A lawyer for the investors declined to comment.
The amended complaint against JPMorgan seeks class-action status, and triple damages for alleged antitrust violations.
It accuses the New York-based bank of having distorted silver prices between 2007 and 2010 by making "repeated manipulative and uneconomic trades."
One series caused COMEX silver futures to drop an unusually large 12 percent on Aug. 14 and 15, 2008, letting JPMorgan reap $220 million on its short positions, the complaint said.
It said JPMorgan would often cause "violent" price swings by placing "fake" trades late in the day, when market activity was thin, at prices "far removed" from what then prevailed.
Tasha Pelio, a bank spokeswoman, said: "These allegations are entirely without merit and we intend to defend ourselves vigorously."
The Commodity Futures Trading Commission began probing allegations of silver price manipulation in September 2008, and last year proposed regulations to give it greater power to thwart traders who try to manipulate prices.
Silver prices have faced regulatory scrutiny in the past, including after the billionaire Hunt brothers drove prices up in 1980 in a failed attempt to corner the market.
The case is In re: Commodity Exchange Inc Silver Futures and Options Trading Litigation, U.S. District Court, Southern District of New York, No. 11-md-02213. (Editing by David Gregorio)