BOSTON (MarketWatch) -- Shares of U.S. Natural Gas Fund (UNG 10.00, -0.59, -5.57%) were down about 6% in active premarket trade Monday after the exchange-traded fund in a regulatory filing late Friday said it plans to resume the creation of new shares on Sept. 28. The natural-gas ETF has been trading at a premium to net asset value since it halted new-share creation over the summer. The ETF's management "cannot predict what impact, if any, the resumption of creation activity will have on the price of the U.S. Natural Gas Fund units on NYSE Arca," according to Friday's filing. "It is possible that the resumption of creation activity, even on a limited basis, could reduce or remove any premium over net asset value," it said. "Investors are cautioned that paying a premium over the net asset value for U.S. Natural Gas Fund units can lead to additional losses for the investor in the event that the investor sells such units at a time when the premium is no longer present in the market price."
