For those keeping an eye on capital flows: $ZRO has broken through the 1.5 level
Key levels usually have clusters of pending orders around them, and big players love to make their move in these areas: first, they may use a breakout accompanied by a surge in volume to drive prices higher; second, they may take advantage of buying from momentum chasers to cash out. To tell the two apart, watch which way trading activity around the price level is skewed.