NEW YORK - United States Natural Gas Fund, an exchange-traded fund in the natural gas market, reiterated on Tuesday that it could invest in interests other than futures contacts to comply with accountability levels and position limits.

UNG told Reuters last month it rebalanced its portfolio to decrease positions in listed natural gas futures, while increasing the fund's holdings in over-the-counter natural gas swamps.

In a filing Tuesday, UNG said it may invest in other interests including cash-settled options on futures contracts, forward contracts for natural gas, cleared swap contracts and over-the-counter transactions based on natural gas, crude oil and other petroleum-based fuels.

UNG said that despite the move futures contracts will remain its principle investment. (Reporting by Edward McAllister; Editing by Lisa Shumaker)