For the current week, the overall ratings of four software stocks are worse, according to the Portfolio Graderdatabase. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Tableau Software, Inc. Class A’s (DATA) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. For more information, get Portfolio Grader’s complete analysis of DATA stock.

SRS Labs (SRSL) earns a D this week, falling from last week’s grade of C. SRS Labs develops and licenses audio and voice enhancement technologies. The stock gets F’s in Earnings Growth and Margin Growth. To get an in-depth look at SRSL, get Portfolio Grader’s complete analysis of SRSL stock.

Actuate Corporation (BIRT) earns an F (“strong sell”) this week, moving down from last week’s grade of D (“sell”). Actuate provides software and services to develop and deploy Rich Information Applications. The stock gets F’s in Earnings Revisions, Earnings Surprise and Margin Growth. For more information, get Portfolio Grader’s complete analysis of BIRT stock.

KongZhong Corp. Sponsored ADR (KZ) gets weaker ratings this week as last week’s C drops to a D. To get an in-depth look at KZ, get Portfolio Grader’s complete analysis of KZ stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.