These are markets which are in economies which are significantly poorer or less developed than the major international stock markets (US, Japan, Western Europe), or whose rules and regulations prevent international investors from carrying out the same kinds of transactions as in larger markets. In general, emerging markets tend to have stronger economic growth and produce higher stock market returns than developed markets. But they will also usually have considerably higher risk, for a whole range of reasons. While it’s difficult to be too general, it’s probably true to say that they tend to do well compared to developed markets when markets throughout the world are rising, and that they do somewhat worse when world markets are falling. They are usually seen as more risky markets than the developed markets, and for this reason it’s generally a good idea to take a long-term approach when investing there.