Wall Street's top regulator on Wednesday was set to approve new rules on funding a market surveillance system meant to split its development and operating costs between brokerages and stock exchanges while allowing the latter several years to recoup hundreds of millions already spent.

The pending decision by the five-member U.S. Securities and Exchange Commission marks the latest fraught turn in a decade-long effort to complete the so-called Consolidated Audit Trail, a repository of investor and transaction data meant to give regulators overarching visibility into U.S. market operations.

(Reporting by Douglas Gillison)