Spending Flows

July 19, 2015

In the past few weeks I have been unfolding an origami of sorts. In the past 7 years, the Federal Reserve has created almost $4 trillion of new money.  Contrary to centuries of history that this would cause prices to rise dangerously, inflation has been muted during the five years of this recovery.  Core inflation, which excludes more volatile food and energy items, has been below the 2% target inflation rate that helps guide monetary policy decisions at the Federal Reserve.

In a standard expenditures or spending model, personal saving is presumed to flow through the banking system into business investment.  This approach can be helpful in understanding changes in investment spending and the difference between planned and unplanned investment.  However, that model presumes that consumers have little choice in the direction of their personal savings; that these savings flows are controlled entirely by the investment spending decisions made by business owners. I proposed a different way of looking at savings – as a form of spending shifted backwards in time.  We anticipate different rates of return based on the amount of time we shift investment forward or backward in time.

Economist John Maynard Keynes proposed that one person’s income is some else’s spending.  In the private domestic economy then, consumption spending, investment and savings are forms of spending.  We can combine them into one simple accounting identity.

If these components of total spending add up to 1, then

If we subtract yesterday’s and tomorrow’s spending from total spending we get the percentage that is today’s spending.

This concept was proposed by Keynes as the Marginal Propensity to Consume, or MPC.  In the example below the MPC is .9.  If there is an extra $1 of spending in the economy, people will tend to spend 90 cents of that extra $1 on today’s consumption.

Where does that extra $1 of spending come from?  Keynes proposed that the government could step in and spend money when there was a lack of consumption spending in the economy.  Last week I said that I would cover the role that government plays in the economy but I will leave that for next week.

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