The Globe and Mail reports in its Wednesday, April 1, edition that everyone has an opinion on central bank rate decisions amid the energy shock from the Iran war, but for now, the answer may be to hold steady because a tightening of financial conditions has already occurred. A Reuters dispatch to The Globe reports that the Chicago Federal Reserve's index of U.S. national financial conditions tightened significantly in March, reaching its most restrictive level since last May, the largest monthly change since President Donald Trump's tariff announcement last April. Goldman Sachs's equivalent U.S. measure was in tune with the Chicago Fed version. Its euro zone gauge also hit a 10-month high, though the March jump was less extreme than in America. So why does it matter? Central bank policy changes can be powerful, but only insofar as they change the real cost of borrowing for households and businesses. If markets are already doing that job -- through tighter loan costs, higher mortgage rates, energy-driven spending hits and lower stock prices -- then the net effect of a central bank rate hike may already be playing out. Since the start of the Iran war markets have priced out up to two expected Fed rate cuts this year.