A long-delayed plan that’s supposed to help U.S. regulators get to the bottom of what causes stock market disruptions is getting a renewed push.

The Securities and Exchange Commission is set to release its proposal for creating a massive repository to track billions of daily orders and quotes. The idea, which SEC commissioners are scheduled to vote on Wednesday, has been kicked around for at least five years.

Lawmakers have grown increasingly frustrated over the SEC’s failure to finish what’s known as the consolidated audit trail, particularly as market breakdowns erode investor confidence. While the most significant malfunction was the May 2010 flash crash for equities, as recently as Aug. 24 many stocks opened late on the New York Stock Exchange and experienced wild price swings.

Regulators say the audit trail could help them reconstruct market crises and quickly analyze data for equities and options markets across multiple exchanges and trading platforms. It’s meant to fill a blind spot for the SEC, which has struggled to keep up with trading that’s now mostly electronic and rapid-fire. The agency initially said it would cost $4 billion a year to build and $2.1 billion annually to maintain.

Unique Identifiers

Under the SEC’s plan, every trading firm and broker would have a unique identifier, so regulators can tie companies to specific transactions. Exchanges would be responsible for submitting data to the repository that lays out the date and time that orders and bids occur. The SEC, Financial Industry Regulatory Authority and exchanges would have access to information in the database.

“While Finra and the exchanges currently maintain their own separate audit trail systems, and have worked diligently to improve them, these systems do not provide ready access to all of the data points necessary for effective oversight,” SEC Chair Mary Jo White said in a statement. “The consolidated audit trail is critical to achieving this objective, and it will generate enormous benefits for the SEC’s mission.”

White said the system will achieve enormous benefits for investors by enabling the agency to more quickly analyze and reconstruct events like the “flash crash” and ETF gyrations in August. In praising CAT, Commissioner Kara Stein said the system is critical for the SEC to insure fair and orderly markets. Commissioner Michael Piwowar said it the has promise of new and powerful means of surveillance across multiple markets.

Public Comment

SEC commissioners are scheduled to vote Wednesday on whether to seek public comment on the plan for 60 days. If approved in a second vote, exchanges would then have to start reporting data to the audit trail within one year. Large brokerage firms would have to start submitting data within two years, followed by smaller firms one year later. Finra and the exchanges get to pick which company builds the audit trail.