Definition of mosquito for English Language Learners. : a small flying insect that bites the skin of people and animals and sucks their blood.
What it is: Small-cap stock refers to a company with a market capitalization (calculated by taking a firm's current share price and multiplying that figure by the total number of shares outstanding) near the low end of the publicly traded spectrum.
A typical definition would be companies with a market capitalization of less than $250 or $300 million. The smallest public companies, with market capitalization of less than $50 million, are sometimes referred to as 'nanocap stocks.' This guide will use the term 'microcap stock' to refer to both microcaps and nanocaps.