UPDATE 1-El Pollo Loco shares go crazy in debut, fly 32 pct

* Shares open at $19, above IPO price of $15

* Values company at over $700 mln at day's high

(Adds details)

July 25 (Reuters) - Shares of El Pollo Loco Holdings Inc rose as much as 32 percent in their market debut as investors tucked into the offering, betting on the growing popularity of the restaurant chain's fire-grilled chicken.

El Pollo's shares rose to $19.84 in morning trading on Friday on the Nasdaq.

El Pollo Loco, Spanish for "the crazy chicken", raised $107.1 million after its initial public offering of 7.1 million shares were priced at $15 each, the higher end of the range. All the shares in the IPO were offered by the company.

Private equity firms Trimaran Capital Partners LLC and Freeman Spogli & Co owned the company through Trimaran Pollo Partners LLC prior to the offering. Their stake fell to 80 percent after the IPO.

El Pollo Loco fire-grills its chicken in an open kitchen, allowing diners to see their meals being cooked. Since opening its first restaurant in Los Angeles in 1980, the chain has grown to more than 400 branches across the southwestern United States.

The company says it combines the convenience of quick service with the quality of food expected of fast-casual chains.

With an average check of $5.83 per person, a visit to El Pollo Loco is more expensive than dining at McDonald's Corp or Wendy's Co, but cheaper than Chipotle Mexican Grill Inc or a Subway sandwich.

El Pollo Loco first filed for an IPO in 2006. It withdrew its registration later that year citing unfavorable market conditions, before receiving a $45 million funding from Freeman Spogli in 2007.

The Costa Mesa, California-based company has franchised 60 percent of its business. Drive-through business accounts for about 40 percent of its sales.

El Pollo Loco's revenue rose 7.2 percent in 2013 to $314.7 million on the back of 11 straight quarters of rising same-store sales through the quarter ended March 26.

The company's annual loss widened to $16.9 million last year from $7.9 million, due to early repayment of debt. El Pollo Loco will use the proceeds of the IPO to repay debt.

Jefferies LLC and Morgan Stanley & Co LLC were the lead underwriters for the offering.

(Editing by Savio D'Souza and Saumyadeb Chakrabarty)