SOES, Definition
The Small Order Execution System or SOES is an automated execution system that routes orders of up to 1,000 shares directly to Nasdaq market makers. Market makers can have one order executed against them automatically for every 20 seconds they remain on the inside bid or offer. The SOES system was implemented after the crash of 1987 in an effort to provide liquidity for the public/retail trader. The participation of Nasdaq market makers in SOES became mandatory in 1988 as a result of the fact that retail customers were largely unable to access market maker quotes during the recent crash.