McDonald's McMuffin is hammering rivals

After doubling down on breakfast, McDonald's is eating competitors' lunch.

Since the fast food giant announced plans to extend breakfast hours, its stock price has far outpaced several rivals that also depend on the morning meal for business.

McDonald's shares have risen nearly 25 percent since the Sept. 1 announcement, while shares of other breakfast servers like Denny's, Bob Evans, Cracker Barrel, Dunkin' Brands and IHOP owner DineEquity are off by double digits.

"McDonald's was a huge laggard in an industry that was a major outperformer. It's been a popular trade to be long McDonald's on speculation that all-day breakfast is driving positive comps and contributing to market-share gains," said Andy Barish, a restaurant analyst at Jefferies, in a phone interview. Jefferies has a "hold" rating and $100 price target on McDonald's stock.

"The big question is how positive are same-store sales and whether or not it's going to impact the rest of the QSR sector," he added.

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McDonald's has not shared exactly how much of a boost breakfast has provided so far this quarter, but there's evidence it is luring customers back to the Golden Arches.

A third of McDonald's customers who bought breakfast at non-breakfast hours during the first month of the program had not purchased the chain's food in the five-week period before the launch, NPD found after analyzing more than 27,000 McDonald's receipts.

NPD also found 61 percent of receipts during lunch time also included non-breakfast items, which helped fuel an increase in average check size.

"McDonalds is capturing a lot of the growing number of Americans that are going out to eat" amid low gas prices and improving employment trends, said Will Slabaugh, a Stephens managing director, in a phone interview.

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While Slabaugh thinks Dunkin is ceding share to McDonald's, he does not think McDonald's is "stealing a massive amount of share from peers" broadly.

Still, rivals' stocks are suffering due to anticipation McDonald's is taking share, he added.

Wall Street will have to wait until late January when McDonald's releases its earnings report to get a true read on breakfast.

—CNBC's Dominic Chu contributed reporting to this article