We compare execution quality of six brokerage accounts across five brokers by generating a sample of 85,000 simultaneous market orders. Commission levels and payment for order flow (PFOF) differ across our accounts. We find that execution prices vary significantly across brokers: the mean...

We placed over 85,000 retail trades at six retail brokers to validate the Boehmer et al. (2021) algorithm, which uses subpenny trade prices to identify and sign retail trades. The algorithm identifies only 35% of our trades as retail, incorrectly signs 28% of trades, and yields uninformative...