| Symbol | Bid | Ask | Spread | |
| Astrazeneca Plc | 73.65 | 73.66 | 0.01 | |
| Astro-Med | 13.52 | 16.79 | 3.27 | |
| Astronics Corp | 15.73 | 15.74 | 0.01 | |
| Astrotech Corp | 10.3 | 11 | 0.7 | |
| Asure Software Inc | 13.75 | 13.78 | 0.03 | |
| At Home Group Inc Cmn | 36.72 | 36.94 | 0.22 | |
| AT&T Inc | 17.09 | 17.09 | 0 | |
| Ata Inc | 1.98 | 1.99 | 0.01 | |
| Atara Biotherapeutics Inc | 2.74 | 2.75 | 0.01 | |
| Atento S.A. | 1.35 | 2.13 | 0.78 | |
| Athenahealth | 10 | 9.99 | 0.01 | |
| Athene Holding Ltd | 84.4 | 84.4 | 0 | |
| Athens Bancshares Corp | 0 | 0 | 0 | |
| Athersys | 0.94 | 0.9769 | 0.0369 | |
| Atkore International Group | 126.08 | 126.08 | 0 | |
| Atlantic American Corp | 2.4 | 2.48 | 0.08 | |
| Atlantic Capital Cm | 32.22 | 34.22 | 2 | |
| Atlantic Power Corp | 3.02 | 3.02 | 0 | |
| Atlantic Tele-Network | 36.17 | 36.17 | 0 | |
| Atlanticus Holdings Corp | 28.59 | 28.59 | 0 | |
| Atlas Air Worldwide Holdings | 102.48 | 102.48 | 0 | |
| Atlas Energy Llc | 0.0092 | 0.0092 | 0 | |
| Atlas Financial Holdings Inc | 0.21 | 0.21 | 0 | |
| Atlassian Cls A Ord | 147.15 | 147.99 | 0.84 | |
| Atmos Energy Corp | 113.72 | 114.6 | 0.88 | |
| Atomera Inc | 8.18 | 8.42 | 0.24 | |
| Atossa Genetics Inc | 0.63 | 0.649 | 0.019 | |
| Atricure | 17.02 | 51 | 33.98 | |
| Atrion Corp | 608 | 629 | 21 | |
| Attunity Ltd | 23.42 | 23.5 | 0.08 |