#8. Eureka: Reserve Banking

previous: #7: Virtualization in Early Banking

Consider a small city served by a single banker-merchant. He has built a safe room to store coins and has a clerk to keep accounts. He has lent out all his own money and, it being a prosperous era, in the past his loans have always been paid back on time and with interest. There are all these coins, really a lot of the coins of this city, sitting in his safe. He can't help thinking that if he could lend them out not only could he earn interest on them, but it would be good for the community. One client wanted a loan for a second fishing boat, which would surely be paid back, since the demand for fresh fish is high. The banker thinks of other clients who would be helped if only he could make loans to them.

Then it strikes him! Like a jolt of lighting, like a burning bush, like Christ speaking to him from the crucifix of the local church. Every day a client or two comes in and deposits or withdraws money. Over time the pile of coins has grown. On no one day do enough clients come in to withdraw all the coins. Eureka! He calls his clerk Big Data and says: go back through the ledgers and find out what the lowest count of coins we've had on deposit in the last five years.

A week later Big Data says: in the last five years we have never had less than 4,000 gold coins on deposit. And how many are on deposit today, our banker asks. 5,282, says Big Data. The banker sends out his clerk to get another blank accounting book.

The new account will record loans to clients that are made using the coin in client deposits. The fisherman borrows 50 coins to buy a new boat. He takes it to the boat builder, who is worried about having 50 gold coins sitting in his workshop or house. So … he takes the coins to the banker and deposits them. The banker will make, perhaps, two gold coins in interest on the loan. The same number of coins are back in the safe as there were at the start. The two gold coins paid in interest along with the original fifty are not even new coins. They are from the banker's stash of depositors' coins. The fisherman has a new boat, the boat builder a small profit, the men who cut timber for the boat have made wages, and the banker is richer.

The banker sees that the system is a closed loop. Most of the coins he loans out come back as deposits. As long as the town is prospering, as long as the total goods owned and services provided continue to grow (as they did in many Italian towns during this period, until the Turks cut off the trade routes to the East and the Portuguese and Spaniards gained monopolies in the West), the Banker can loan out the same coins over and over again. Sometimes coins are traded to outside his loop, but other times coins come in trade from other regions. The coins left in the vault, the ones that are not loaned out because they may be demanded by their owners, are what we call a reserve.

The accounting system is now critical to the banker's success. He has to know who owes him principle and interest, as well as how much he owes depositors. He sees that while he does not have coins to pay all the depositors at once, he does have loans out that will cover the deposits.

Of course, sooner or later, the banker will find that due to a series of withdrawals, he is running out of coins. He knows he'll be okay over time because the loans are still good, and he expects them to be paid in coin. Perhaps his friend who started as a fisherman comes in wanting to make a large withdrawal of coins that will break the bank.

The banker enquires why such a large sum of money is required. The depositor is buying an estate so that he can retire from managing his fishing fleet, leaving it to his son, and enjoy life as the owner of a country estate known for its fine grapes and wines. It so happens that the current possessor of the estate, Luciano,  has borrowed a sizable sum from the bank. The banker suggests that it is dangerous to carry such large sums around. He can facilitate the transaction by giving Luciano a note cancelling his debt along with the coin needed to make up the difference. The fisherman accepts this, and the bank is saved.

Of course in reality the system evolved over time and with many participants, but the idea of the reserve system was a major extension of the accounting system and the beginning of the end for coins. Over the centuries large numbers of banks have failed, some because of fraud but most because they did not keep sufficient reserves. It happened to a few American banks last year and it will happen again next year, and continue as long as the system is used. But on the whole the system of keeping small reserves of coin, and later paper money, and now electronic money, to back a larger accounting of loans and deposits, has worked rather well.

Next: #9: Virtualization with Checking and Credit Cards

[The Accounting System, Your Fate is in the Cloud, is a work in progress by William P. Meyers, ©2013]