The ratings of three software stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

VASCO Data Security International, Inc.’s (VDSI) rating falls this week to an F (“strong sell”), down from last week’s D (“sell”). VASCO Data Security International designs, develops, markets and supports open standards-based hardware and software security systems that manage and secure access to information assets. For Portfolio Grader’s specific subcategory of Margin Growth, VDSI also gets an F. Shares of the stock have been changing hands at an unusually rapid pace, twice the rate of the week prior. The stock has a trailing PE Ratio of 31.80. To get an in-depth look at VDSI, get Portfolio Grader’s complete analysis of VDSI stock.

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. The stock gets F’s in Earnings Growth and Margin Growth. For more information, get Portfolio Grader’s complete analysis of SRSL stock.

The rating of TeleNav, Inc. (TNAV) declines this week from a D to an F. TeleNav provides personalized mobile navigation service in the United States and internationally. The stock gets F’s in Earnings Growth, Earnings Revisions, Margin Growth and Sales Growth. The stock price has dropped 6.4% over the past month, worse than the 1.3% decrease the Nasdaq has seen over the same period of time. The trailing PE Ratio for the stock is 45.60. To get an in-depth look at TNAV, get Portfolio Grader’s complete analysis of TNAV 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.