/u/theringinginmyears posted a very interesting question in ELI5, and it didn't get any good answers. I'm particularly interested in the result of abolition on loans made with slaves as collateral, but I imagine s/he wants all their questions answered.

I recently saw "Twelve Years A Slave" and "Django" and it inspired me to do more research on the topic of slavery and the general associated economics. A few sources have suggested that a slave may have cost around $1200 around 1860. In today's terms, this would have been around $30,000. Put in perspective, a slave may have cost as much as a good car. Being relatively expensive, it seems that this industry spawned a related financial industry dedicated to loans (mortgages) on slaves. Much like a house, an individual slave was used as security (or collateral) on these loans. All this makes logical sense, but I still have a few gaps in understanding:

1. It appears that slaves were a major investment and very capital intensive. Death or illness should have had a large economic impact on the process. Morals and customs aside, would it not be in the best financial interests of the slave owners to maintain the health and productivity of their slaves?
2. Were the slave owners really so wealthy that they could kill something worth the cost of a modern car for no good reason? Even most modern wealthy people don't go around destroying $30,000 cars for fun.
3. Using slaves as security to back loans seems like very unwise collateral. A simple farming accident could render the security completely worthless. Present banks loan money on real security such as land and buildings which are obviously far more secure than a human life. Why would a bank in the 1800s even consider such a risky form of security?
4. In the event of a default, were the foreclosures or repos on slaves? Would the bank come and take the slaves if payments were not made on the mortgages?
5. After the abolition of slavery, I assume that the value of the security dropped to zero. Were there massive defaults? Did it bankrupt many once rich and powerful families and companies? Or, did the banks and financial institution simply write off the losses now that their collateral was worthless?