What is "PNK" from market column within Yahoo! Finance? The other example of market is "Toronto".

Answer 1

This tells you want "market" the shares are listed on. For example, a share can trade on Nasdaq or the New York Stock Exchange.

Canada has its own markets, most famously the Toronto exchange. While many large Canadian companies trade on the NYSE or Nasdaq (e.g. Nortel, Encana), there are plenty that still trade on Toronto stock exchange (e.g. Westjet).

PNK is "pink sheets". The Pink Sheets is an electronic exchange, but is not registered with the SEC and has no listing requirements. Stocks listed on this exchange do not have the required minimum characteristics (e.g. volume, market cap, ownership) to be listed on other exchanges (e.g. AMEX, Pacific, NYSE, Nasdaq). This means they are usually quite small, illiquid and unfortunately very, very risky.