Obamacare penalizes firms that don’t provide health insurance.  If a firm has fewer than 50 employees, however, it’s exempt:

Requires employers with 50 or more employees who do not offer coverage to their employees to pay $2,000 annually for each full‐time employee over the first 30 as long as one of their employees receives a tax credit.

This is hardly an isolated example.  Countless other regulations exempt small business.  To take another random example, Title VII discrimination laws originally only applied to firms with 100+ employees.

Why do I bring this up?  To me, this looks like another important counter-example to the left-libertarian view that regulation, not free-market forces, explains the dominance of big corporations in the modern economy.  Left-libertarians, what say you?