Recent amendments to work visa rules published in the federal register (and that took effect on January 17, 2025) enables being a founder of a company while on an H-1B, and perhaps might similarly allow that for a TN, but Peter Roberts or another expert would likely know best about it.
Thanks. The law never has explicitly prohibited founders from qualifying for H-1B or TN status but there have been challenges and the changes mentioned above will make it easier for founders to qualify for H-1B status and I think make it easier for founders to qualify for TN status. In fact, we recently had a founder obtain a TN through CBP and her status as a founder was front and center in her application.