From True Slaves To Wage Slaves

Bloomberg (h/t Ritholtz):

The U.S. won its independence from Britain just as it was becoming possible to imagine a liberal alternative to the mercantilist policies of the colonial era. Those best situated to take advantage of these new opportunities -- those who would soon be called "capitalists" -- rarely started from scratch, but instead drew on wealth generated earlier in the robust Atlantic economy of slaves, sugar and tobacco. Fathers who made their fortunes outfitting ships for distant voyages begat sons who built factories, chartered banks, incorporated canal and railroad enterprises, invested in government securities, and speculated in new financial instruments.
This recognizably modern capitalist economy was no less reliant on slavery than the mercantilist economy of the preceding century. Rather, it offered a wider range of opportunities to profit from the remote labor of slaves, especially as cotton emerged as the indispensable commodity of the age of industry.
In the North, where slavery had been abolished and cotton failed to grow, the enterprising might transform slave-grown cotton into clothing; market other manufactured goods, such as hoes and hats, to plantation owners; or invest in securities tied to next year's crop prices in places such as Liverpool and Le Havre. This network linked Mississippi planters and Massachusetts manufacturers to the era's great financial firms: the Barings, Browns and Rothschilds.
A major financial crisis in 1837 revealed the interdependence of cotton planters, manufacturers and investors, and their collective dependence on the labor of slaves. Leveraged cotton -- pledged but not yet picked -- led overseers to whip their slaves to pick more, and prodded auctioneers to liquidate slave families to cover the debts of the overextended.
The plantation didn't just produce the commodities that fueled the broader economy, it also generated innovative business practices that would come to typify modern management. As some of the most heavily capitalized enterprises in antebellum America, plantations offered early examples of time-motion studies and regimentation through clocks and bells. Seeking ever-greater efficiencies in cotton picking, slaveholders reorganized their fields, regimented the workday, and implemented a system of vertical reporting that made overseers into managers answerable to those above for the labor of those below.
The perverse reality of a capitalized labor force led to new accounting methods that incorporated (human) property depreciation in the bottom line as slaves aged, as well as new actuarial techniques to indemnify slaveholders from loss or damage to the men and women they owned. Property rights in human beings also created a lengthy set of judicial opinions that would influence the broader sanctity of private property in U.S. law.

Now workers are only owned most of the week.  Really, in the slave economy, labor was invested capital.  There wasn't the struggle between labor and capital.  It gives a different view of capital investment multiplying in value.