SEC Approves Plan for Massive Stock Data Trove

After years of wrangling, the Securities and Exchange Commission approved a plan to build a massive repository of stock and options trades to help regulators quickly get to the bottom of why markets crash.

The system known as the Consolidated Audit Trail, or CAT, has been billed as an essential step to improve monitoring and understanding of market moves. With the 3-0 vote by the commission Nov. 15, now it’s up to stock exchanges to decide within the next two months who will win the lucrative contract to build the data trove. The three finalists include a team featuring Google parent ...