U.S. options market operators have agreed in recent months on the need for new automatic trading halts when stock options prices suddenly surge or plunge, in a bid to reduce excess volatility and blunt the impact of erroneous trades, according to five sources with knowledge of their discussions. The plan, which takes its cue from a rule known as "Limit Up/Limit Down" that U.S. stock markets put in place in response to the May 6, 2010 "Flash Crash," is still in the early stages, with market operators trying to figure out how a similar rule could be applied to options trading, the sources said.  In the ... (full story)