| Period | Weighting | Quarter | ||||||
|---|---|---|---|---|---|---|---|---|
| Company | Longest | Shortest | Min. | Avg. | Max. | First | Latest | ↓ Count |
| GROUP ONE TRADING, L.P. | 5 | 1 | 0.00% | 0.00% | 0.00% | Q2 2013 | Q3 2021 | 16 |
| SIMPLEX TRADING, LLC | 14 | 2 | 0.00% | 0.00% | 0.00% | Q3 2017 | Q4 2021 | 16 |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | 13 | 13 | 0.00% | 0.00% | 0.00% | Q3 2018 | Q3 2021 | 13 |
| Citadel Advisors | 2 | 2 | 0.00% | 0.00% | 0.00% | Q4 2013 | Q1 2014 | 2 |
This page lists all the filers that currently own ZIX CORP or have owned ZIX CORP in the past.