But they don't, and that's because the definition varies with the user.
Many investment managers do.
Mutual funds with small-stock images include such stocks in portfolios. Nothing stops them from doing so. Arriving at a definition is especially important now, since so many advisers are recommending what they say are laggard small stocks, reasoning that such stocks will soon have their time in the sun. The smalls have been there before. Experience shows that small shares may have cycles of activity and rising prices, returning to investors a premium that cannot be explained by risk factors alone.