A former 4th wave price extreme at 1.6680 held as resistance today and the GBPUSD may have topped. At least a portion of the 5 wave advance from 1.5775 should be retraced (Fibonacci support between 1.6116 and 1.6326) if not the entire thing. Coming under 1.5775 would suggest that top is in place. Given the 5 wave count from 1.4513 (wave C of the rally from 1.35), it is worth going short.