December marked the fifth-year anniversary of ACON Investments’s acquisition of Peter Piper Pizza.

Founded in 1973, the Phoenix, Ariz.-based company operates more than 135 casual dine-in pizza restaurants in the Southwestern United States and Mexico, according to the ACON Investments Web site. In September, the company opened the first of a projected 25 restaurants in the Houston, Texas region, according to a Sept. 21 report in the Houston Business Journal.

Peter Piper serves basic and specialty pizzas in various sizes, and is a venue for birthday parties and other events (“Chuck E. Cheese is Vegas for kids. Peter Piper Pizza is Atlantic City,” a reviewer for The Arizona Republic quipped in a July 2011 story.) Its newer facilities feature 10,000-square foot layouts, flat-screen televisions, free Wi-Fi and beer and wine. The company ranked third among the top 50 U.S. pizzerias in sales, according to the company’s Web site, which cites Pizza Magazine’s “Pizza Power Report 2009.”

The Washington, D.C-based buyout firm bought Peter Piper from Madison Dearborn Partners and Golub Capital in December 2006 (Madison Dearborn had invested $12.75 million in the company in 1995, according to Capital IQ). Terms of the deal were not released, though ACON Investments typically invests $20 million to $150 million of equity into its deals.

Firm Founder and Managing Partner Bernard Aronson told Buyouts in an e-mail that “we don’t believe Peter Piper is ready for sale,” but was unable to comment further because he was traveling.

ACON Investments, meanwhile, is raising its third fund. Buyouts reported in January 2012 that it had raised $400 million for the fund, which is seeking $600 million.