NEW YORK ( TheStreet) -- These six stocks were upgraded by TheStreet Ratings to a buy on Tuesday: Southwest Airlines ( LUV), Macerich ( MAC), Hologic ( HOLX), Beam ( BEAM), Diebold ( DBD) and Associated Banc-Corp ( ASBC). Southwest Airlines The airline on Tuesday said revenue passenger miles in January fell 2.7% from the previous year to 7.4 billion. Southwest also announced last week that it was adding flights from Denver and Austin, Texas to Cancun. "Southwest Airlines expects 2012 capacity to be flat with 2011, which will help the company to improve passenger unit revenue to offset higher y/y jet fuel prices," Dahlman Rose analysts wrote in a Jan. 20 report. "With no capacity growth this year, Southwest expects mid- to high-single digit passenger unit revenue growth. January and February are expected to see growth of 7%-8%, with March expecting to slow." Southwest Airlines was upgraded to a buy from a hold by TheStreet Ratings. Of the 17 analysts who cover the stock, eight rated it a buy and an equal number considered it a hold. One analyst gave Southwest a sell rating. Southwest has an estimated price-to-earnings ratio for next year of 8.91. The average among the airlines is 8.46. Both Delta ( DAL) and United Continental Holdings ( UAL) have lower forward P/Es of 4.1 and 3.92, respectively. TheStreet Ratings gives Southwest a B- grade with a $11.60 price target. The stock closed Monday at $9.75; it has risen 13.9% year to date.