The American Stock Exchange, like the New York Stock Exchange, is a physical exchange that have a bargaining transaction through commissioners and brokers.
However, the market value of stocks listed on the American Stock Exchange is relatively small, the same as the China growth enterprise market.
Nasdaq is a non-physical exchange that trades through an integrated system, with more technology stocks and growth stocks.
OTCBB is the over-the-counter stock market in the United States,but there are no market capitalization, minimum share price, corporate governance or other requirements to be quoted.
OTCBB'stock also requires disclosure to SEC, but trading is not active because of the poor quality of these companies.