This time the curve has become inverted mainly because long-term yields have fallen so much.

ECONOMIST: Bond bombshell

Even Palm's trajectory might have been different if it had inverted its thinking in time: Imagine a Palm Pilot not as a personal information manager with connectivity, but a connected device with PIM applications, and you have described exactly what the smartphone is today.

CNN: Is Apple losing its cool?

But what if we inverted these assumptions and gave each student the time needed to master concepts so that all students earned As?

FORBES: How to Bring Quality Online Education to a Global Student Population

At one time analysts liked to do this by quoting the yield gap (though this became inverted when dividend yields fell below bond yields in the 1950s) or the yield ratio, both of which relate share to bond yields.

ECONOMIST: A survey of global equity markets: Valuation waltz | The