"Corporate profits are eating the economy," Derek Thompson wrote yesterday. And indeed, it seems they are. Company earnings are reaching new highs as a share of GDP. Wages are falling to new lows. And the stock market is surging. 

It's not just that corporations are taking a bigger bite out of the country's wealth, though. It's the banks in particular. And that's an important part of understanding why workers are falling behind, while shareholders are pulling ahead. 

Thirty years ago, the financial sector claimed around a tenth of U.S. corporate profits. Today, it's almost 30 percent. As a result, it's supplanted manufacturing as the biggest profit center in the economy, a transformation I've graphed out below. The red line is manufacturing. The blue line is the finance sector chowing down like Pac Man on corporate America's bottom line.

Wall Street's haul peaked in the early 2000s at around 40 percent of all corporate profits. And while it fell hard during the financial crisis, finance has since recovered to its dotcom boom share.

Now here's how all this relates to jobs. In the midcentury economy, when manufacturing was raking in 40 to 50 percent of corporate profits, it was also responsible for a around 20 to 30 percent of all employment. Finance, on the other hand, has never been responsible for more than 5 percent (as shown below). 

So the problem isn't inherently that the makers lost out to the bankers. It's that profits shifted from a high-employment industry to a low-employment industry. And even though the whole pie of profits has grown, it still means earnings and, ultimately, wealth, end up concentrated in fewer hands, whether they belong to traders earning bonuses or shareholders earning dividends.  

There's a coda to this story. After the early 2000s, manufacturing recovered its relative profitability, but it kept slashing jobs -- off-shoring some and using computerization and high-tech machinery to replace others.

In the Age of Wall Street, finance didn't just eat the corporate world. It also seems to have taught other industries to mimic its high-profit, low-employment template. Today, finance and manufacturing together account for more than half of domestic profits. They employ around one-eigth of the workforce. And that's how corporate profits eat an economy.