James Tobin, Banking And The Widow’s Cruse

There is good discussion in the blogosphere on James Tobin’s 1963 paper Commerical Banks As Creators Of “Money” – also mentioned in my previous post Holier Than Tobin?

This blog post is an attempt to present Tobin’s ideas from the paper in a more simplistic way.

One of  Tobin’s points is a critique of the notion that since loans create deposits, it makes banks special as compared to non-bank financial institutions and the over-emphasis on this point by many.

Tobin goes on to show how this is misleading. The fact that a non-banking financial institutions don’t simply credit shares like banks is not too important.

From the viewpoint of a single bank, while loans make deposits, the deposits can “fly out” to another bank and hence the bank is limited by its deposit raising ability. In general, a bank can fund itself by using other things – not just  deposits – so a bank will need to fund itself. It is sometimes said that “banks lend first and look for deposits later” but this is a bit misleading because while it is true in general, it is in the confident knowledge that the funding will be available at a not so costly rate. If the bank fears or the whole banking system fears a funding crisis, then lending will be curtailed.

It is true that the bank can fund itself from the central bank but even this is not available for unlimited amount. It has to provide collateral to the central bank which is limited. Usually these are marketable securities and not loans provided to the private sector and the amount of marketable securities is a small fraction of banks’ balance sheet.

At a macro level however, deposits leaving a bank may move to another bank so one may conclude that the banking sector as a whole collectively possesses a Widow’s Cruse.

Tobin however goes on to show how the presence of non-banking financial institutions (NBFIs) presents problems for such a view – by hook or crook, the banking system has to induce the non-banking private sector to hold deposits with them than depositing it with NBFIs. In general flight of deposits abroad is also important. This comes at a cost – the easiest to think of is the interest rate paid on deposits but one can also think of other things such as advertising costs etc.

In the following I show how this happens and how the banking system’s balance sheet can shrink because of flight of deposits to NBFIs who can take away banks’ market share. The fact that loans create deposits is not so important as is emphasized many times. Even though non-banks cannot simply credit the “share” account  doesn’t mean much. They can keep attracting deposits from banks and lend.

So let us take a simple example: start with a bank with initial balance sheet of 100 units. I will neglect capital and other liabilities to keep things clean so if you are not comfortable you can always change the liabilities side by reducing deposits by say 10 and replacing it with other liabilities. Also I call NBFIs’ liabilities “shares” and this is more like money-market mutual fund shares and shouldn’t be confused with stock-market shares.

t = 0

Banks

Assets: Loans = 100
Liabilities: Deposits = 100

Non-Financial Private Sector

Assets: Deposits = 100
Liabilities: Loans = 100

Non-bank Financial Institutions

Assets: Deposits = 0
Liabilities: Shares = 0

t = 1

At t = 1, let us say NBFIs attract 10 units of deposits from bank depositors. So the balance sheets will look like:

Banks

Assets: Loans = 100
Liabilities: Deposits = 100

Non-Financial Private Sector

Assets: Deposits = 90, Shares = 10
Liabilities: Loans = 100

Non-bank Financial Institutions

Assets: Deposits = 10
Liabilities: Shares = 10

t = 2

At t = 2, someone extinguishes his/her/its loan to the banking system by 10 unit. So,

Banks

Assets: Loans = 90
Liabilities: Deposits = 90

Non-Financial Private Sector

Assets: Deposits = 80, Shares = 10
Liabilities: Loans = 90

Non-bank Financial Institutions

Assets: Deposits = 10
Liabilities: Shares = 10

t = 3

At t = 3, someone borrows 10 units from NBFIs. So,

Banks

Assets: Loans = 90
Liabilities: Deposits = 90

Non-Financial Private Sector

Assets: Deposits = 90, Shares = 10
Liabilities: Loans = 100

Non-bank Financial Institutions

Assets: Loans = 10
Liabilities: Shares = 10

NBFIs who had 10 units of deposits no longer have it because they have lent 10 units which involves transfer of deposits. The net result at the end is that banks have lost a share of 10 units out of the initial 100 to non-banks and also deposits worth 10 units.

This of course can go on and it is in the interest of banks to prevent this from happening and induce the public to bank with them. In Tobin’s asset allocation theory, asset demands are dependent on the portfolio preference parameter and also the interest rate paid on the asset (or expected returns in general). So putting up interest rates on deposits would prevent this shift to non-bank financial intermediaries.

Tobin would say that “at this point the widow’s cruse has run dry”. Perhaps there is an over-emphasis on this but I leave it to the reader to decide.

One thing Tobin didn’t emphasise is the role of effective demand. I would imagine he would explain why lending doesn’t explode by using some neoclassical marginal curves instead of the Post-Keynesian answer.

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