Yen shorts are at a 5-year high.

The weekly CFTC data released Friday show net yen shorts at 79K, a surge from 51K a week earlier.

The data is collected at the close each Tuesday.

The most frightening part is that even as yen shorts piled on (from Tues, Nov 20 to Tues, Nov 27) USD/JPY rose just 47 pips.

If you’re long USD/JPY or any other yen cross beware.