IPO Full Form is Initial Public Offering. IPO refers to the first stock sold by a company to the public. Most often, companies that offer IPO would be small, young, or new companies. At times, though a company has been for many years, it might be going public and hence performs the IPO. IPOs are often risky to invest; but can also offer potential gains.
Most often, this is the way small companies or beginners gain the required market capital. When a company decides to go public, the first step it takes is to hire investment bank. The first IPO occurred in 1602 March. This was when Dutch East India Company gave away shares to public to raise capital. All shareholders were given proper receipts for their purchases and all trades of the company was tradable.