Auguste Reymond established his namesake watch company in 1898 in Tramelan. Like most watchmakers at the time, he used movements from a variety of producers before beginning ebauche production on his own around 1906. Movement production began in Bioux but was moved to Tramelan soon after. Reymond purchased the existing Unitas Watch Company in 1926 and used that name on his ebauches, movements, and some complete watches.
In 1932, Reymond and Unitas came under the ASUAG umbrella, with the Unitas ebauche operation falling under Ebauches SA. The Unitas trademark stamp, a letter “T” inside a letter “U” was established at this time.
In the 1950's, Unitas released two famous pocket watch movements, calibres 6497 and 6498. These large (19 ligne) hand-wound movements would continue in production until the present under the ETA banner.