Many of these companies remain private with so many resources available for investment

The list is led by oil and gas producer Apache Corp.

The state of Ohio ranks at the top

The nation's largest retailer Wal-Mart easily tops the list by employing the most people in 20 states

The big North American and European defense corporations have secured their place among the top 10 arms dealers

The San Jose metro area in Calif. contributed 47.5% of economic output in 2013, the highest among large U.S. cities