Boeing Shares Tumble as Much as 44% Before Rebounding By Clyde Eltzroth and Whitney Kisling - Jun 28, 2010 Email Share Business Exchange Twitter Delicious Digg Facebook LinkedIn Newsvine Propeller Yahoo! Buzz Print Two transactions involving Boeing Co. shares showed the aircraft maker sank 44 percent today before rebounding to within $1 of last weekâs closing price. While regulators are trying to prevent swings in the price of individual companies from causing another crash like the May 6 rout, a program being tested through December only applies after 9:45 a.m. in New York. Boeing, which ended at $68.77 on June 25, tumbled to $38.77 at 7:14 a.m. today. Nasdaq OMX Group Inc. handled 200 shares at that price, and NYSE Euronext processed 800, according to data compiled by Bloomberg. The stock changed hands for $68.23 at 8:17 a.m., and NYSE canceled the order it handled, Bloomberg data show. Companies such as Accenture Plc, which now fetches $40.55, traded for 1 cent on May 6 as U.S. stocks lost $862 billion in value in less than 20 minutes. The Securities and Exchange Commission pilot program pauses trading for Standard & Poorâs 500 Index companies, including Chicago-based Boeing, when their stock rises or falls 10 percent or more in less than 5 minutes. U.S. exchanges, building on the circuit-breaker test, offered rules this month that would standardize the process for breaking erroneous stock trades. The proposal, also for S&P 500 companies, would void orders when they occur more than 5 percent above or below the level that would trigger a halt. A voicemail message left with Boeingâs media office before regular business hours in Chicago wasnât immediately returned. Nasdaq OMX spokesman Robert Madden didnât immediately respond to phone calls or e-mails requesting comment. NYSE Spokesman âWeâve been discussing the subject of circuit breakers with the SEC, and those discussions are ongoing,â NYSE Euronext spokesman Ray Pellecchia said in an interview. âThe clearly erroneous rules have been revised, so thatâs the next thing the SEC is considering.â Three equity orders that pushed Washington Post Co. shares up 99 percent in less than one second on June 16 showed why the SEC began the program this month to halt stocks during times of volatility. Trades totaling 766 shares at $919.18 or $929.18 crossed on NYSE Euronextâs NYSE Arca platform at 3:07:30 p.m. in New York that day, data compiled by Bloomberg show. The stock changed hands for $462.84 prior to the jump. The orders, later canceled, triggered a five-minute halt under rules adopted after the May 6 crash.