A quote from The Machinery of Freedom

How much would it cost workers to purchase their firms? The total value of the shares of all stocks listed on the New York Stock Exchange in 1965 was $537 billion. The total wages and salaries of all private employees that year was $288.5 billion. State and federal income taxes totalled $75.2 billion. If the workers had chosen to live at the consumption standard of hippies, saving half their after-tax incomes, they could have gotten a majority share in every firm in two and a half years and bought the capitalists out, lock, stock, and barrel, in five. That is a substantial cost, but surely it is cheaper than organizing a revolution. Also less of a gamble. And, unlike a revolution, it does not have to be done all at once. The employees of one firm can buy it this decade, then use their profits to help fellow workers buy theirs later.

When you buy stock, you pay not only for the capital assets of the firm—buildings, machines, inventory, and the like —but also for its experience, reputation, and organization. If workers really can run firms better, these are unnecessary; all they need are the physical assets. Those assets—the net working capital of all corporations in the United States in 1965—totalled $171.7 billion. The workers could buy that much and go into business for themselves with 14 months’ worth of savings.

Would have been nice if it was updated for the third addition but demonstrates it was possible.

Edit: Trying to get more up to date numbers. Some comments are on old data I had.

The most recent numbers I can find for total wages and salaries are from the May 2014 National Occupational Employment and Wage Estimates United States.

As of last month (January 2016) the Market cap for the New York Stock Exchange was 16,813 trillion. World Federation of Exchanges you have to make an account get the data.

usgovernmentrevenue.com