The filing does not yet specify how many shares the chain will offer up, or at what price. Nor does it offer a date when the filing will take place.

El Pollo Loco was sold in September by American Securities LP to Trimaran Capital Partners. At the time, the chain--which had mostly run restaurants on the West Coast and Southwest--was expanding East, opening its first Chicago store in October. As noted in the company's SEC filing, it plans to open 52 restaurants in existing markets by 2009, as well as 44 in Illinois, New York, the six New England states, Colorado and Washington during the same time period.

In 2005, the company posted a same-store sales gain of 8.2% year over year on revenues of $237 million. Same-store sales have risen 5.4% since 2000.

Food-borne illness, negative publicity, the spread of avian flu and increasing costs of chicken are among the risks that management lists in its filing. "The food service industry, and particularly the quick-service and fast-casual segments, is intensely competitive," it also notes.

El Pollo Loco is Spanish for "the Crazy Chicken." The company, which started in Mexico, opened its first US unit in Los Angeles in 1980. The chain offers marinated, flame-grilled chicken and other foods made with fresh ingredients. About 60% of its units are franchised, while the rest are company owned.

El Pollo Loco's IPO follows other recent restaurant chains going public. Cracker Barrel is spinning off its Logan's Roadhouse concept, Burger King management announced an IPO a few months ago, and last year's IPOs included Chipotle Mexican Grill and steakhouse chain Ruth's Chris.