50% retracement is also in play on the the downside
The GBPUSD tried to move lower and back below its 200 hour moving average in the Asian session, and although there were looks below that MA line (see green line in the chart below), the 50% midpoint of the last move down from the September 23 high to the September 29 low could not also be broken.
As a result in the European session, the price rotated back to the upside only to run into resistance from yesterday's high and the swing area between 1.36403 and 1.36537. The high price reached 1.36422 and has seen a rotation lower in the early US session.
The fall takes the price back down toward the 200 hour moving average 1.35894. The 50% is at 1.35805. Both levels would need to be broken to increase the bearish tilt. Recall back on September 27 and September 28, the price tried to move above its 200 hour moving average only to fail rather quickly (within a couple hours of trading).
The move to the upside yesterday has seen the price stay above that moving average for more of an extended time, but overhead resistance still provides a headwind for buyers (and a sell area for sellers).
Buyers and sellers have defined their lines in the sand (or areas in the sand). Traders will look for the next break.