A spine-chilling slide of nearly 1,000 points in the Dow Jones Industrial Average, its biggest intraday points drop ever, led to heightened calls for a crackdown on computer-driven high-frequency trading.
The slide, which in one 10-minute stretch knocked the index down nearly 700 points, may have been triggered by a trading error. Major stock indexes eventually recovered from their 9 percent drops to close down a little more than 3 percent.
But the follow-through selling that pushed stocks of some highly regarded companies into tailspins exacerbated concerns that regulators can quickly lose control of the markets in a world of algorithmic trading.
"The potential for giant high-speed computers to generate false trades and create market chaos reared its head again today," Senator Edward Kaufman said in a statement.
"The battle of the algorithms -- not understood by nor even remotely transparent to the Securities and Exchange Commission -- simply must be carefully reviewed and placed within a meaningful regulatory framework soon."
Kaufman and Senator Mark Warner -- both Democrats -- said Congress needs to investigate the causes of the market plunge, which at its deepest point wiped nearly $1 trillion off equity values.