Best Buy’s third-quarter profit more than quadrupled, but its shares were down more than 6 percent in early trading on expectations its fourth-quarter profit margins will be squeezed by shoppers who choose lower-cost TVs and laptops.

Best Buy reported net earnings of $227 million for its third fiscal quarter compared with $52 million for the year-ago period.

The mobile phone category was among those that experienced the largest gains, along with flat-panel televisions, digital imaging and notebook computers. The company has been putting more emphasis on mobile phones with its Best Buy Mobile store-within-a-store concept.

The company noted that domestic comparable store sales improved sequentially each month of the third fiscal quarter, finishing with an 8.4 percent increase in the fiscal month of November as the company saw low-double digit comparable store sale gains on Friday and Saturday of the Thanksgiving holiday shopping weekend.