On the consumer banking side, a more normal yield curve would benefit banks like Morgan Stanley due to a better lending environment as banks can borrow short-term rates and lend long-term.
To see what was going on, Dr Hansen superimposed the actual curves for each decade from the fifties to the noughties on a normal distribution, which acted as a reference curve.
It used to be that Wall Street was functioning on the basic idea that financial events were subject to something very like a normal distribution, also known as a bell curve.