An exchange traded fund that invests in companies that are active in the exploration and mining of lithium and battery producers rose on Monday with A123 Systems (NasdaqGS: AONE) leading the way following an upgrade at Morgan Stanley.

A123 Systems shares rallied about 13%. Morgan Stanley boosted its rating on the stock to overweight from equal weight, saying it expects the firm to unveil a major contract by January, according to Bloomberg.

The shares account for nearly 4% of Global X Lithium ETF (NYSEArca: LIT).

“Demand for lithium has increased dramatically in recent times, and investment here will require a strong positive thesis for sustained demand increase going forward,” Morningstar says in a profile of the fund. “Lithium is a commodity, a rare earth metal, but investors should understand the mechanics of this fund before attempting to use [the ETF]as a proxy for spot lithium.”

Unlike some other commodity ETFs, the lithium fund invests in stocks rather than physical lithium or futures contracts.