Ankle Biter

What Does Ankle Biter Mean?
Stock issues with a market capitalization of less than $500 million.

Also known as "small cap" stocks. 

Investopedia explains Ankle Biter
These issues can appear to be more speculative than stocks with high market capitalization. However, smaller issues often have great growth potential and tend to outperform larger market capitalization stocks. Small cap stocks are often biting at the ankles of the larger cap stocks and will one day - through capitalization growth - move up into the larger market capitalizations, as a child grows into adulthood.