I have co-founded one successful company and am a co-founder in a current startup. I do think explicitly about tax effects when making business decisions, and

I have co-founded one successful company and am a co-founder in a current startup. I do think explicitly about tax effects when making business decisions, and there are definitely tax rates that would have changed my decisions, particularly taxes on wealth or investment income that make it less valuable to have savings. High enough taxes could also cause me to leave the U.S. Regulation, however, is a much bigger impediment to innovation than (current levels of) taxes - there are no companies that I have not started because of taxes, but there are a dozen that I haven't started because regulations would make them impractical or make political influence more competitively important than good execution.