The rationale behind this trade is mostly technical: the forming in SPY , suggesting indecision regarding the future evolution of US Equities, seems to have a bias.
This could reflect the greater likelihood of a move down for the foreseeable future: Valuations are high, the dollar remains expensive, SPY got a 30bn outflow on January, the Fed rate hike seems like could come sooner than some economists forecast...
Hence, I find the current prices good enough for a short position. The stop will be put in place in case we breakout to the upside.. Everything's possible and there's no worse idea than trade without stops. May add more if there's a sign of a false breakout.