This week, the overall grades of four Software stocks are lower, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This week, SRS Labs (NASDAQ:SRSL) falls to a D (“sell”), worse than last week’s grade of C (“hold”). 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. For more information, get Portfolio Grader’s complete analysis of SRSL stock.

Slipping from a C to a D rating, TeleNav, Inc. (NASDAQ:TNAV) takes a hit this week. TeleNav provides location-based solutions. The stock gets F’s in Earnings Growth, Earnings Momentum, and Margin Growth. For a full analysis of TNAV stock, visit Portfolio Grader.

Red Hat, Inc.’s (NYSE:RHT) rating weakens this week, dropping to a D versus last week’s C. Red Hat provides open source software solutions that customers are allowed to update, monitor and manage. The trailing PE Ratio for the stock is 66.20. To get an in-depth look at RHT, get Portfolio Grader’s complete analysis of RHT stock.

This week, Taomee Holdings Ltd. Sponsored ADR’s (NYSE:TAOM) rating worsens to a D from the company’s C rating a week ago. Taomee Holdings produces children’s entertainment. The stock gets F’s in Earnings Surprise and Margin Growth. For more information, get Portfolio Grader’s complete analysis of TAOM 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.