CHICAGO — McDonald’s hefty new Angus burger appears to be ready to hit the national stage in August, according to an internal company document obtained by the Chicago Tribune.

The document refers to a national launch for the one-third pound Angus between Aug. 3 and Aug. 30. McDonald’s Corp., based in Oak Brook, Ill., said it doesn’t comment on speculation and leaked documents.

McDonald’s began testing the burger in Southern California in March of 2007, and later began selling it in New York and Columbus, Ohio. Made from a higher grade of beef than other McDonald’s burgers, the Angus is the fast-food giant’s most expensive U.S. sandwich, priced about $4.

In April, the Tribune reported that the Angus was set to go national this fall, and possibly as early as summer. The burger is expected to be a part of McDonald’s annual “Monopoly” promotion in October, according to an internal company document.

In October, McDonald’s management told stock analysts the Angus wouldn’t roll out nationally for at least a year, according to a research report written then by a stock analyst at Stifel Nicolaus. The weak economy was given as one reason for the wait.

The economy has only grown worse since then. Still, new products tend to generate buzz and a surge of customer traffic. It’s not clear whether the Angus would have a permanent place on McDonald’s menu.