Primary market is the financial market in which a security is first sold by the issuer and bought by investors, before further changing hands (or owner).
Equity shares of a company are sold for the first time in an IPO, the primary market in this case.
For NFOs, the initial issue and distribution of investment fund units are done on the primary market.
Bonds, when issued for the first time are subscribed in the primary market.
In the case of ETFs, primary market is where the initial block unit is created by an AMC in lieu of the underlying securities that make up an ETF’s basket. At the other end of the primary market, are market makers, authorised participants, institutional investors.
Any large investor may also access the primary markets if looking to buy thousands of ETF units by nudging a creation unit-holder to release more ETF units.
Once the security is issued in the primary market, it is called a seasoned security. Further trading by investors among themselves is done on the secondary market.