Comment by proberts

That's right, a lot of international founders participate in the batch as business visitors, whether under ESTA or a B-1 visa. The most common post-batch work authorization options are the country-specific visas (for those from Australia, Canada, Chile, Mexico, and Singapore), the O-1, and the E-2. If based abroad and only coming to the U.S. for investor meetings and the like, then you could continue as a business visitor but practically this can become a problem if traveling to the U.S. regularly; at some point CBP will push back.