ITC Holdings exploring strategic alternatives, including sale

* Co working with two investment banks on the sale - source

* National Grid, Iberdrola SA may consider bidding - Bbg (Changes sourcing, adds details from company statement)

Nov 30 (Reuters) - U.S. power transmission company ITC Holdings Corp said it was exploring strategic options, including a sale, as increased energy efficiency weakens demand for electricity.

The company is working with two investment banks on the sale, although it is in early stages, a person familiar with the matter told Reuters.

Shares of the company rose as much as 13 percent, after Bloomberg earlier reported that the company was exploring a sale.

Utilities companies including U.K.-based National Grid Plc and Spain's Iberdrola SA may consider bidding for ITC, according to the report.

"Our Board of directors is focused on creating value for our shareholders and so we are conducting a review of strategic alternatives to ensure that we are doing that," Chief Executive Joseph Welch said in a statement.

ITC owns and operates 15,600 miles of lines in six Midwest states, serving a combined peak load of more than 26,000 megawatts.

The Novi, Michigan-based company's shares were up 9.3 percent at $36.88 in extended trading on Monday. ITC's shares have fallen 8.8 percent this year.

(Reporting by Mike Stone in New York and Narottam Medhora in Bengaluru; Editing by Anil D'Silva)