Oklahoma stocks swell and swoon during just-ended quarter

On the other hand, Tulsa-based Apco Oil & Gas International was punished by traders for operating in a political hot spot: Argentina.

In April, Argentina's president announced a measure that would allow the country to seize nearly all of the local assets of Spanish energy giant Repsol. Although Apco officials said they didn't expect that action to affect its operations, the stock has been on a sharp decline.

Shares of Apco Oil & Gas fell 73 percent in the second quarter to close Friday at $18.05. At the beginning of the year, the stock traded for more than $80 a share.

For Sonic, the return of the “two guys” advertising campaign helped boost the firm's fortunes in the April through June period, Vaughan said. The television ads feature two comic actors in the front seat of a car at Sonic touting the company's food and drinks.

“We did change advertising agencies in early 2011,” Vaughan said. “We moved to a different creative. I think we figured out — it took us a few months — that didn't work best for our brand. The two guys, people immediately recognize them as representing the Sonic brand.”

The campaign helped get the word out to customers about Sonic's latest offerings, designed to capture customers throughout the day, Vaughan said.

Unlike many of its competitors, Sonic produces less than half of its revenue at lunch and dinner by focusing on afternoons and late evenings with offerings such as happy hours, he said.

The firm reported better-than-expected results in its growth of same-store sales, a key metric that tracks sales of drive-ins open for at least a year. Profits also grew, which pleased franchise owners who operate most of the company's more than 3,500 drive-ins, Vaughan said.

Vaughan said the company successfully introduced new products such as real ice cream to replace soft-serve, and sweet potato tots.

This summer, Sonic will debut some new slush flavors, a couple of new hot dogs and a cookie dough and brownie batter concoction, Vaughan said.