New York (CNN Business) Video game company Activision Blizzard suspended three American University esports players for six months after they held up a "Free Hong Kong, boycott Blizz" sign during their championship match last week.

They now cannot compete in official or third-party Blizzard events.

The college sophomores, Casey Chambers, Corwin Dark and Torin Wright--all 19 years old and majoring in international studies--prepared a sign in reaction to Ng's ban and showed it on a stream of their college game October 8. The ban occurred Tuesday, one week later, according to Chambers.

Blizzard confirmed to CNN Business Wednesday that it banned the three students after they "knowingly broke" the rules. In a statement, the company said: "We strongly encourage everyone in our community to share their viewpoints in the many places available to express themselves. However, our official broadcast needs to be about the game and the competition, and to be a place where all are welcome."

Read More