Nissan North America has extended its $10,000 rebate on the all-electric Nissan Leaf car in Hawaii.

Hawaiian Electric Co. announced Wednesday that Nissan added three months to its original deal on the Leaf for electric utility customers on Oahu, Hawaii island and in Maui County. Customers can now qualify for $10,000 off the sticker price of a Leaf until June 30.

Nathan Hartmann, assistant marketing professor at the University of Hawaii at Manoa, said Nissan could be stuck offering the rebate price.

“Extending the large rebate for such a long time is likely to desensitize Leaf consumers to future rebates and result in consumers deferring purchases on other Nissan models as they begin to associate rebates with Nissan and look for a rebate prior to purchasing,” he said.

Hartmann said competition plays a role in the extended rebate — Nissan is set to face two major new competitors in the same price range from Chevy and Tesla in the Hawaii market this year.

The Chevy Bolt begins sales in Hawaii in September, and the Tesla Model 3 will be arriving by the end of the year. The manufacturer’s suggested retail price for the Bolt is $36,620. Chevrolet’s electric vehicle has nearly twice the range of the Leaf — rated at 238 miles per battery charge. The $35,000 Model 3 gets an estimated 215 miles from one charge.

The Leaf, with a suggested retail price of $30,680 for its 2017 model, can travel an estimated 107 miles on one charge. Nissan is planning to come out with a redesigned Leaf for the 2018 model year, according to Car and Driver magazine.

When combining the rebate with federal tax incentives, some customers are able to save up to $17,500 on a 2016-17 Nissan Leaf. The tax credit varies for EV owners depending on how much they pay in taxes. An EV owner can’t spread the tax credit over multiple years, and it is not refundable.

HECO said Nissan, not electric customers, is paying for the rebate; the utility’s only responsibility is to notify customers of the deal.

The promotion added to the growing number of EVs in Hawaii.

As of March, the electric vehicles in the state numbered 5,502, a 29 percent increase from the same month last year, according to data from the Department of Business, Economic Development and Tourism. There was an increase of 300 electric vehicles since January.

Nissan and HECO announced the promotion on Jan. 25. Customers had to have deposits down by the end of March and the car had to be delivered in April for the new EV owners to qualify.

During the first promotion, dealerships on Oahu reported selling out of inventory, causing customers to sign up for waitlists. The initial promotion resulted in Oahu dealers selling at least 105 cars.

“At one point we were completely sold out,” said Lauren Sanborn, owner loyalty manager at King Windward Nissan.

Sanborn said there is no waitlist at King Windward now, but the dealer is receiving 10 more Leafs this weekend to add to the 24 Leafs on the lot.