The impact of this change on the economy could be disastrous. Its stabilizing effect would be to stabilize the economy on a path of much less growth, and it would mean fewer start-ups, slower expansion for new businesses and correspondingly fewer new jobs and contributions to the GDP. It will also reduce the rate of growth of state and federal tax revenues and those losses will have to be made up from other sources, probably more taxes on consumption and income, which will further drive down the economy. For consumers it means less choice in your 401K or IRA or other investment fund, more regulation, and arbitrary limits on the upward mobility which has been the great hallmark of the American dream.
The only winners in this scenario are the established megacorporations who will see less competition and more control of the marketplace and will likely end up being able to buy out small companies when they reach the size that the might have gone public because those companies will have no other way to get the capital they need to continue to grow. It means fewer, bigger companies which owe their increasingly monopolistic power to the government.
This is not a good model of a business environment for the United States or for its people. It's making the rich richer and the poor poorer, stealing opportunity from the middle class and handing it to the ultra-rich. It shows the hypocrisy of the Democrats whose rank and file love anti-corporate rhetoric, yet keep supporting a leadership which is clearly willing to sacrifice the welfare of the people in order to enrich their fat cat corporate allies and buy their loyalty.