It's a theory at least:
I am inclined to conjecture that over the last 30 years, reductions in top marginal tax rates may have provided a huge incentive to expand the financial services industry. The increasing importance of finance also seems to have been a significant factor in the increasing inequality in income distribution observed over the same period. But the net gain to society from an expanding financial sector has been minimal, resources devoted to finance being resources denied to activities that produce positive net returns to society. So if my conjecture is right — and I am not at all confident that it is, but if it is – then raising marginal tax rates could actually increase economic growth by inducing the financial sector and its evil twin the gaming sector — to release resources now being employed without generating any net social benefit.
(Chart from Bernard Finel)