Not always. Whether a property is subject to Rent Control depends on a number of factors.
If the property is owned by a person(s) then so long as the owners do not own more than 4 units then they are exempt from Rent Control. Trust are not always exempt and depends on whether the units were registered previously with an exemption. If the property was registered as exempt by the owners of the Trust previous to changing it to the trust the property generally remains exempt. However, if the property was not registered previously each unit no matter how few would automatically be bound to rent control.
If the property is owned by an entity (Corporation, LLC, Partnership or any other form of ownership besides an individual person you are automatically subject to rent control no matter how many or few units are owned.
There are exceptions to Rent Control. For instance, if the property was built after 1985 its automatically exempt no matter how its owned or how many properties are owned in the case of individuals.