If you happen to be the only one with negative interest rates, you also weaken your currency, which means you make your exports more competitive.

How long can interest rates stay negative? Think about this. Not only are you lending your money to governments, but you're paying them interest for the privilege of doing so.

[When] the market is trying to get to terms with, first, lower global growth, particularly out of emerging markets and China. And, second, the market is worried the central banks have run out of ammunition. So put these two things together, and then investors are repricing the market lower.

The world is on a bumpy journey to a new destination and the New Normal.

America's downgrade may serve as a wakeup call for its policymakers. It is an unambiguous and loud signal of the country's eroding economic strength and global standing. It renders urgent the need to regain the initiative through better economic policymaking and more coherent governance.

Investors should be cautiously positioned as the global economy and markets face major uncertainties. The downgrade will be a further headwind to growth and job creation in the U.S.

Investors have to ask themselves two questions. How much can we grow our investments? And, can we afford our mistakes?