It’s a sign of changing times. IPO market is picking up again. This week is the biggest week for IPO in the last 18 months. So far this week, five companies raised a total of $2.97 billion making it the biggest for IPO money-raising since the week of April 20, 2008. Another deal from Chinese company Shanda Games is on the way today. The pipeline of companies planning to go public in the U.S. has also been growing over the past two months, with 20 companies filing new registrations with the Securities and Exchange Commission since the beginning of August.

Yesterday, electric-car battery maker A123 systems came out with their IPO and saw the stock soaring 50% on the first day of trading. The company hasn’t made any profits so far. Another hot IPO, Shanda Games Ltd, is coming to market today. It’s expected to trade with the symbol “GAME”. Shanda priced its initial public offering at the high end of expectations and would sell up to $1.04 billion in equity.

If you are getting into these IPOs, keep in mind that first day gains are mostly bubble. Investing in companies with short track record is very risky. It may go in either direction.