Quote from pspr:
Here is a very simplified explanation.
Usually, the market continues to move up even as inflation begins and the Fed starts to tighten (they have several methods available to them of tightening or raising short term rates). This is because the economy is surging and corporate profits are increasing despite the beginning of inflation and slightly higher interest rates and corporate profits can keep increasing into this for some time.
However, at some point, interest rate increases start to slow the economy because of the increasing costs to both consumers and corporations which cuts into corporate earnings which eventually will slow and/or reverse the inflation tendencies as demand drops and corporations begin cutting costs and lowering prices to move product.
The most friendly way inflation rates start rising is when manufacturing capacity utilization reaches near capacity and manufacturers start raising prices to increase profits. This happens because corporations can no longer increase profits by manufacturing more product without making large expenditures for plant and equipment. So they naturally begin raising prices more frequently because demand is there.
The more harmful way inflation rates start increasing is from one or more widely used (needed) commodities start experiencing rapid price increases.
A good example of the latter was the oil crisis caused by OPEC in the 1970's. Rapidly increasing oil prices created rapidly increasing costs in almost every sector of the economy resulting in price increase spirals. Only after new Fed Chairman Volker increased rates to astronomical levels was he able to reign in economic growth and put the clamp on increased oil usage and the resulting inflationary spiral we were in.
Of course, this created a deep recession and cost Jimmy Carter the White House but there was no other way out of the double digit inflation we were experiencing by the time Paul Volker was hired to do the job.
We could talk about why a little inflation is good but hyper inflation is bad but that is another book entirely.