Answer:
primary market
Step-by-step explanation:
The primary market is where securities are first issued. E.g. a company's IPO represents a primary market, or when bonds are first issued.
Most trading occurs in secondary markets, i.e. they trade securities that have been already issued and are owned by investors that are willing to sell them. A single stock could theoretically be traded hundreds of times in the secondary market, but they can only be traded in the primary market once (when they are issued).