Newton's first law of motion states that the velocity of a body remains constant unless the body is acted upon by an external force. In the arena of exchange-traded funds, sectors and ETFs with strong momentum can often continue on strong trajectories, and July's "sector of the month" was silver, as the white metal has been white hot.

Precious metals, and silver, in particular, were the leading sector in July in response to the debt ceiling crisis and a "flight for safety" from a potential US. default.