The Securities and Exchange Commission is expected to tighten U.S. stock market listing rules beginning in August, after relaxing requirements in the wake of the global financial crisis.

The SEC had lowered the minimum price threshold for companies to remain on the New York Stock Exchange in February, and the Nasdaq Stock Market in October.

Officials at NYSE Euronext (NYX) and Nasdaq OMX Group Inc. (NDAQ) don't plan to request an extension of the relief beyond its planned expiry on July 31, as most of the troubled listees have seen their stock prices resume trade above the key $1 threshold.

"There is much less of a reason for us to push for an extension as there was when we originally requested the moratorium," said Scott Cutler, head of listings for the Americas at NYSE Euronext, in an interview.

Representatives of the SEC declined comment.

Both NYSE Euronext and Nasdaq OMX have rules requiring listed companies to maintain a minimum price of $1 per share.

If a stock trades below $1 for 30 consecutive business days, companies usually are given 180 days to fix the issue or face delisting.

Nasdaq OMX suspended its minimum bid price requirements last October with the approval of U.S. regulators, at a time when the exchange's delistings were double the previous year's level.

NYSE Euronext asked the SEC for permission to relax its own dollar standard for U.S. stocks in late February, a month after the exchange lowered its market value standard to $15 million from $25 million.

The moves offered relief to companies that saw their share prices pummeled in a market slide that eventually wiped out about half the value of the Dow Jones Industrial Average.

Temporarily suspending listings standards also helped ease pressure on the exchanges, for which listings represent a source of revenue.

In March, more than 100 NYSE-listed stocks were trading under a dollar or approaching that level, Cutler said, but since then about three-quarters of those names have recovered and climbed back above the threshold.

Nasdaq OMX declined to provide figures detailing the number of Nasdaq-listed companies that have resumed trade above $1, but spokeswoman Silvia Davi said that "quite a few companies have benefited" from the relaxed standards.

Some names have gone the other way. For the year through July 10, 72 companies have been delisted from Nasdaq OMX markets, compared last year's total of 85.

NYSE Euronext reported 24 companies delisted from its U.S. markets so far this year, about half the exchange's 2008 total, which was the highest in five years.

Cutler said that temporarily easing standards for remaining listed on the NYSE had the "rightful effect" in boosting investors' confidence that the NYSE-listed stocks they owned would not wind up trading on the pink sheets.

"At the time when [we] put in place the moratorium, there was not a clear understanding of the duration of the crisis," said Cutler. "In hindsight today, the market itself corrected a lot of these problems."

NYSE Euronext shares were down 1.5% in midmorning trade at $25.54, with Nasdaq OMX down 1.2% at $19.61.

-By Jacob Bunge, Dow Jones Newswires; 312-750-4117; jacob.bunge@dowjones.com