Anger at trading outages focuses on clearing firm Apex Apex Clearing caused many popular stock trading apps to pause GameStop orders this week 29 January 2021 • 4:34pm Controversial restrictions on retail investors trading popular stocks have been pinned on a little-known company that handles trades for multiple online brokers. Several internet platforms that stopped investors from buying shares in GameStop, AMC and headphone company Koss on Thursday said the blackout was due to Apex Clearing, a company that facilitates trades for the brokerages. Apex, seen as the market leader for providing clearing services, told its customers it was shutting off purchases of the shares on Thursday, leaving the brokerages with no choice but to restrict trading.