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”).

SRS Labs (SRSL) is on the decline this week, earning a D (“sell”) after receiving a C (“hold”) last week. SRS Labs develops and licenses audio and voice enhancement technologies. In Portfolio Grader’s specific subcategories of Earnings Growth and Margin Growth, SRSL also gets F’s. To get an in-depth look at SRSL, get Portfolio Grader’s complete analysis of SRSL stock.

The rating of TeleNav, Inc. (TNAV) slips from a C to a D. TeleNav provides personalized mobile navigation service in the United States and internationally. The stock gets F’s in Earnings Growth, Earnings Momentum and Margin Growth. The stock price has fallen 12.4% over the past month, worse than the 1.3% decrease the Nasdaq has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of TNAV stock.

Red Hat, Inc. (RHT) is having a tough week. The company’s rating falls from a C to a D. Red Hat provides open source software solutions that customers are allowed to update, monitor and manage. The stock currently has a trailing PE Ratio of 61.20. To get an in-depth look at RHT, get Portfolio Grader’s complete analysis of RHT stock.

This week, Taomee Holdings Ltd. Sponsored ADR (TAOM) drops from a C to a D rating. Taomee Holdings produces children’s entertainment. The stock gets F’s in Earnings Surprise and Margin Growth. The trailing PE Ratio for the stock is 32.20. For a full analysis of TAOM stock, visit Portfolio Grader.

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.