To assist class action defense attorneys anticipate the types of cases against which they will have to defend, we provide weekly, unofficial summaries of the legal categories for new class action lawsuits filed in California state and federal courts in the Los Angeles, San Francisco, San Jose, Sacramento, San Diego, San Mateo, Oakland/Alameda and Orange County areas. We include only those categories that include 10% or more of the class action filings during the relevant timeframe. This report covers the time period from May 21 – 27, 2010, during which time 48 new class actions were filed in these California state and federal courts. While labor law class actions generally top the list by a wide margin — often accounting for more than half of the new class action filings in any particular week — this past week only 20 new labor law class actions were filed, representing only 42% of the total number of new class actions filed. The only other category to break the 10% threshold involved alleged violations of California’s Unfair Competition Law (UCL), which includes false advertising claims, with 5 new filings (representing 10% of the total number of new class actions filed).