- ATCLF — AdvanceTC Limited
- ATCMF — Atico Mining Corporation
- ATCN — Atec, Inc.
- ATCV — ATC Venture Group Inc.
- ATCX — Atlas Technical Consultants, Inc.
- ATD.TO — Alimentation Couche-Tard Inc.
- ATDRF — Auto Trader Group plc
- ATDRY — Auto Trader Group plc
- ATDS — Data443 Risk Mitigation, Inc.
- ATDY.NE — PURPOSE COUCHE-TARD (ATD) YIELD SHARES ETF
- ATEAY — Atea ASA
- ATEC — Alphatec Holdings, Inc.
- ATEK — Athena Technology Acquisition Corp. II
- ATEN — A10 Networks, Inc.
- ATEPF — Astra Exploration Inc.
- ATER — Aterian, Inc.
- ATEX — Anterix Inc.
- ATEYY — Advantest Corporation
- ATFV — Alger 35 ETF
- ATG.AX — Articore Group Limited
- ATGFF — AltaGas Ltd.
- ATGGF — Actinogen Medical Limited
- ATGL — Alpha Technology Group Limited
- ATGN — Altigen Communications, Inc.
- ATH.AX — Alterity Therapeutics Limited
- ATH.TO — Athabasca Oil Corporation
- ATHA.CN — Athena Gold Corporation
- ATHC — Accelerated Technologies Holding Corp.
- ATHE — Alterity Therapeutics Limited
- ATHHF — Aether Catalyst Solutions, Inc.
- ATHM — Autohome Inc.
- ATHOF — Athabasca Oil Corporation
- ATHR — Aether Holdings, Inc. Common Stock
- ATHR.CN — Aether Catalyst Solutions, Inc.
- ATHS — Athene Holding Ltd. 7.250% Fixe
- ATI — ATI Inc.
- ATIG — Atlantis Internet Group Corp.
- ATII — Archimedes Tech SPAC Partners II Co. Ordinary Shares
- ATIIU — Archimedes Tech SPAC Partners II Co. Unit
- ATIIW — Archimedes Tech SPAC Partners II Co. Warrant
- ATIW — ATI Networks, Inc.
- ATIXF — AnalytixInsight Inc.
- ATKR — Atkore Inc.
- ATLC — Atlanticus Holdings Corporation
- ATLCL — Atlanticus Holdings Corporation 6.125% Senior Notes due 2026
- ATLCP — Atlanticus Holdings Corporation
- ATLCY — Atlas Copco AB
- ATLCZ — Atlanticus Holdings Corporation 9.25% Senior Notes due 2029
- ATLFF — Atlas Copco AB
- ATLKY — Atlas Copco AB
- ATLO — Ames National Corporation
- ATLPF — Atlas Copco AB
- ATLX — Atlas Lithium Corporation
- ATM.AX — PT Antam (Persero) Tbk
- ATMH — All Things Mobile Analytic Inc.
- ATMP — Barclays ETN+ Select MLP ETN
- ATMU — Atmus Filtration Technologies Inc.
- ATNE — Alternative Energy Technology, Inc.
- ATNI — ATN International, Inc.
- ATNM — Actinium Pharmaceuticals, Inc.
- ATNNF — Autoneum Holding AG
- ATNPQ — Atlantis Technology Group
- ATO — Atmos Energy Corporation
- ATOGF — AUTO1 Group SE
- ATOM — Atomera Incorporated
- ATON — AlphaTON Capital Corp.
- ATONY — Anton Oilfield Services Group
- ATOS — Atossa Therapeutics, Inc.
- ATOXF — Quantum Critical Metals Corp.
- ATP.AX — Atlas Pearls Limited
- ATPC — Agape ATP Corporation
- ATR — AptarGroup, Inc.
- ATR.AX — Astron Limited
- ATRA — Atara Biotherapeutics, Inc.
- ATRB.NE — AGF TOTAL RETURN BOND FUND
- ATRC — AtriCure, Inc.
- ATRL.TO — AtkinsRéalis Group Inc.
- ATRO — Astronics Corporation
- ATROB — Astronics Corporation
- ATRRF — Altarea SCA
- ATRX — Adhera Therapeutics, Inc.
- ATS — ATS Corporation
- ATS.AX — Australis Oil & Gas Limited
- ATS.TO — ATS Corporation
- ATSX.TO — Accelerate Enhanced Canadian Benchmark Alternative Fund
- ATTBF — Abattis Bioceuticals Corp.
- ATTGF — Auto Italia Holdings Limited
- ATTOF — Atento S.A.
- ATTRF — CapitaLand Ascott Trust
- ATUSF — Altius Minerals Corporation
- ATUUF — Tenaz Energy Corp.
- ATV.AX — Activeport Group Limited
- ATVDY — Atresmedia Corporación de Medios de Comunicación, S.A.
- ATVK — Ameritek Ventures, Inc.
- ATVVF — Australian Vanadium Limited
- ATWT — ATWEC Technologies, Inc.
- ATX.AX — Amplia Therapeutics Limited
- ATX.TO — ATEX Resources Inc.
- ATXG — Addentax Group Corp.
- ATXI — Avenue Therapeutics, Inc.
