Janney Capital Markets raised its same-store sales estimate on Taco Bell Tuesday and said parent company Yum Brands Inc.YUM, -1.77% should consider spinning off the taco chain. Analyst Mark Kalinowski raised his fourth-quarter same-store sales estimate on Taco Bell by four percentage points to a range of 5% to 6%. Taco Bell is Yum's largest U.S. operating segment, comprising an average of 97% of its annual profits and 21% of total operating profit. Its performance is expected to outshine Yum's brands in China this quarter, with Yum projecting a sales decline of about 20% in that region. Kalinowski, who raised Yum to buy late last year partially on the premise of a potential Taco Bell spinoff, said the diverging sales trends highlight "one reason we continue to advocate for Yum to find a tax-efficient way to separate Taco Bell." He said the disappointing trends in China, while comprising 35% of Yum's total operating profit, aren't indicative of a slowdown in the U.S. Shares of Yum closed at $72.43 on Friday. They are about flat on the year, compared with a 10% increase for the broader S&P 500. marketwatch