A “flash crash” that can send the overall average of blue chip stocks down 1,000 points in 10 minutes, and where individual stocks can lose more than 90 percent of their value in 10 seconds, remains a looming risk to capital markets, according to the chief financial officer of Accenture, the large global consulting firm.

"Based on what we've all witnessed in the markets that day and since then, there is every reason to expect that this can happen again,’’ said chief financial officer Pamela J. Craig, in an appearance before the Joint Advisory Committee of the Securities and Exchange Commission and the Commodity Futures Trading Commission on market events Wednesday morning.

Her company’s stock was possibly the most brutally affected by the events of May 6. At 2:40 p.m., the stock was trading at $41.01 a share. But in a small window of 10 seconds 10,400 shares, she said, traded at unusually low prices. Most notable: 19 trades of 100 shares each, at a penny each.

She attributed the plunge to “a seemingly perfect storm of economic news around the globe, a reduction of liquidity in many securities, unusual trading volumes and some technology challenges."

Craig called for “clear, coordinated and consistently applied” rules across all exchanges, to head off a repeat of Accenture’s experience.

In its case, the stock, which is listed on the New York Stock Exchange, traded down from $41.01 a share to $38, in the space of 360 seconds, from 2:40 p.m. to 2:46 p.m.

That triggered the NYSE’s version of a circuit breaker on the stock, slowing down trading. Such a Liquidity Replenishment Point is designed to let the market catch its breath and resume trading at realistic prices.

In Accenture’s case, the lowest recorded trade on the NYSE was $38.75 a share that day, she said.

The unusually low trades occurred on other venues, where trading continued but where the NYSE’s action – slowing or stopping trades – was not followed, she said.

Any trade below $16.40 got busted, ultimately, based on exchanges’ agreements that any trade that was 60 percent off from the day’s high or low should be voided.

But there is a lingering effect. Records still show a 52-week-low of $17.74 a share for Accenture’s stock, due to the activity on May 6. That, she said, “is not the true 52-week low.”

"We strongly beliieve that in times of market stress, all markets should operate under the same circuit breaker rules in order to promote orderly markets and investor as well as business confidence," she told the commission.