WASHINGTON — Congress is about to open a new, real-time window into its members’ stock trades, real estate deals and other financial transactions, allowing anyone to view the information online within weeks of the investments.

The frequent reporting requirement also will cover top congressional aides and other senior government officials, including the president and the vice president — about 28,000 executive branch employees by one count.

Making lawmakers and other officials report their investment transactions every 30 days or 45 days, depending on the final language, is a key component of legislation explicitly prohibiting them from trading on insider information.

Both the House and Senate overwhelmingly approved different versions earlier this month and final passage is expected soon. The next step is up to Senate Majority Leader Harry Reid, D-Nev., who can bring the House’s slightly narrower version to a vote or let a House-Senate conference work out the differences.

Insider trading is already illegal and there’s no exemption for government officials. But the perception persists that it’s taking place in the halls of Congress, perpetuated by occasional investigations and media reports of key lawmakers buying, selling or holding stocks or real estate in areas where they influence policy.

The Office of Congressional Ethics is now looking at the trading activities of Rep. Spencer Bachus, R-Ala. In the two months surrounding the 2008 financial collapse and subsequent $700 billion bailout passed by Congress, he made more than three dozen trades.

Bachus, now chairman of the House Financial Services Committee but then its senior Republican, participated in closed briefings on the crisis by Federal Reserve Chairman Ben Bernanke and then-Treasury Secretary Henry Paulson. He’s denied using inside information, and subsequent records show he incurred a net loss of $19,490.

With Congress enjoying only a 19 percent approval rating, according to the latest Associated Press-GfK poll, lawmakers are eager to be seen as reformers early in an election year. Timely exposure of their own financial transactions is a step in that direction, according to watchdog groups.

“The reporting requirement is the best part” of the insider trading law, said Melanie Sloan, executive director of Citizens for Responsibility and Ethics in Washington. “People will know what members and staff are buying and selling. If they’re profiting through their positions in Congress, that will be revealed.”