Stupid headline of the day

"Dollar Soars as China Surprises Markets with Reserve Requirement Hike" (source not disclosed out of kindness).

The dollar may be "soaring" (by a full 0.81% !) today, and China may have hiked rates, but the two events are in no way related. You see, when a country has a fixed exchange rate, it has no control over monetary policy: reserve requirement hikes will induce more hot money inflows (looking for a higher return then dollar-denominated money funds, with no currency risk vs. the dollar), which means a higher money supply - since the central bank has to print the yuan needed to be sold to foreigners in exchange for foreign currency so as to keep the exchange rate constant. China has tried to sidestep this with controls on capital flows but everyone knows they are looser than the US-Mexico border. This is econ 101 and is known as the impossible trinity.

What is the relation between this and my saying the above headline is stupid? Because if China is hiking rates, it shows at least an intent, a signal if you will, of tightening monetary policy. But as I just discussed, this can only happen if China lets its exchange rate appreciate.

And that would be everything but positive for the US dollar.