- Aavagen
- Abomics
- Absentus
- Acament
- Action-Reaction Games
- Action Squad Studios
- ADA Drive
- Adaptos
- Add Inspiration
- AddSearch
- Adesante
- AdLaunch
- adlearning
- AdminLabs
- Adusso
- Advacam
- Advisus
- Aeromon
- Agendium
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- Aibidia
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- Aiforia Technologies
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- Aina Wireless
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- Aito Intelligence
- Aiven
- AJR Solutions
- Akkurate
- Albert Welding
- Alien Snowboards
- Alinan Taito
- Almerin
- Almondella
- Almost Human
- Alphaville
- Altal
- Altonova
- Altum Technologies
- Alula Energy
- Amandan Healthcare
- Ambronite
- Amped
- Ampner
- Anaxeos
- Angular Velocity
- AnttiPatterns
- Apifonica
- Appchieve
- AppFollow
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- Applixure
- Apprien
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- Arctic Robotics
- Arctic Security
- Arctic Warriors
- Ardilla
- Arex Brokering Finland
- Arilyn
- Arkkeo
- Armada Interactive
- Artific Intelligence
- Artome
- Arvo Mobile
- A.S.Helsingö
- Asimos
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- Asqella
- Assetti
- Astalo Games
- Aste Finland
- Ateljee Amnelin
- Atol Avion
- Atomic Shapes
- Audiodraft
- AudioSauan
- Augmented Climbing Wall
- Augumenta
- Auntie
- Aurealis Pharma
- Aurelia Turbines
- Aurora Propulsion Technologies
- Autolle
- Automarkkina
- AutoVex
- Avanto Technologies
- Aves Netsec
- Axinoss
- Axitare