NEW YORK (CNN/Money) - Much was made of how Aug. 14 would change the investing landscape. That's because the CEOs and CFOs of most large companies had to certify their financial results with the Securities and Exchange Commission.

But Aug. 29 is shaping up to be a pretty important landmark in its own right, and it is one that has received far less attention. Why is this date special? Starting on Aug. 29, if corporate insiders buy or sell stock in their own company, they will have just two business days to disclose the transaction. That's one of the byproducts of the recently passed Sarbanes-Oxley Act, Congress' corporate reform bill.

Under existing rules, insiders have been able to wait until the 10th of the month following a trade. For example, if a CEO sold 50,000 shares in his company on July 2, he would not have had to let the SEC know until August 10. Then there's typically a lag of a few days before investors can find out from a variety of Web sites that track insider-trading patterns.

In some cases, insider transactions didn't even have to be reported for nearly a year. Under current rules, if an insider buys or sells shares from their company's treasury (as opposed to on the open market), the insider could wait until 45 days after the fiscal year in which the transaction was made before disclosing the trade.

The new rule, approved Tuesday by the SEC, applies to both trades with the company and those made on the open market. (see more on the new SEC regulations)

"Insiders" are either executives or directors of a corporation or a person that owns more than 10 percent of the company's stock. They typically are not allowed to trade during the days immediately preceding a major announcement such as an earnings release but are free to do so at other times.

Between the alleged insider trading scandals involving Martha Stewart and ImClone founder Sam Waksal, and news of massive stock dumping by executives at Enron, Tyco and AOL Time Warner, the parent of CNN/Money, investors haven't been this focused on insider trading patterns since the days of Michael Milken and Ivan Boesky.

And as this turbulent summer for the market draws to a close, it will be interesting to see on an almost real-time basis what insiders are doing.

"There's a great deal of interest in getting the information sooner and I'm sure the market is going to appreciate having it," said Evelyn Cruz Sroufe, a partner specializing in corporate finance and securities law with Perkins Coie LLP, a Seattle-based law firm.

The acceleration of the filing process probably will also spur more insiders to file with the SEC electronically. (Another mandate of the Sarbanes-Oxley Act is that all insiders must file this way by June 30, 2003) And by doing so, investors would be able to access the filings immediately through the SEC's Edgar database.

SEC spokesman John Heine said that insiders already have the option of filing electronically but only a "small minority" currently does. The SEC has been pressing more insiders to file electronically since it would speed up the process as well as cut down on mistakes made from transcribing transactions detailed on paper forms.

With a two-day time frame, securities lawyers say insiders will face a greater need to file electronically or they'll risk missing the deadline. And the punishment for not filing on time is that the SEC will publish the tardy filers on the company's annual 10-K report as well as list the late filers in the company's proxy statement right underneath their bio.

Cynthia Krus, a partner in the Washington office of law firm Sutherland Asbill & Brennan LLP, says that corporate clients aren't thrilled about the shorter deadlines but realize that in this market environment, investors will probably punish companies that have executives who don't comply with the new rules.

"I can't say Corporate America is embracing the rule changes but they know the market is sensitive to insider selling," Krus said. "In the early 1990s, not filing in a timely fashion was fairly rampant but people are much more cognizant today."