Pre-IPO Shares are private equity shares which are available in secondary sale. Therefore, It is not a direct Investment in the company. Pre-IPOs are often those companies which have filed the DRHP (Draft Red Herring Prospectus) Papers for IPO, or those companies which haven't been listed yet on the stock exchange. Technically, Unlisted & Pre-IPO Shares are the same.
There are various types of shares available in the market which are divided into different phases :
Pre-IPO : When a company is newly formed & its shares are issued.
Listed Shares : When a company is established enough to raise funds directly from the public via Initial Public Offering (IPO).
Stopped Trading : when shares of any specific company becomes inactive due to lack of interest by the Investors.
Delisted : When a company is undergoing constant heavy losses, It ends up delisting itself from the exchange to cut-off a heavy expense for listing fee.
Liquidation : When a company becomes insolvent, It starts distributing its assets to claimants. It is basically the shutdown phase of a company.