A more thorough explanation:

Dual listing refers to the practice of listing a security on more than one stock exchange. This means that the security is available for trading on multiple exchanges, giving investors more options for buying and selling.

• Company A is listed on both the New York Stock Exchange and the London Stock Exchange. This means that investors can buy and sell shares of Company A on either exchange.
• Company B is only listed on the Tokyo Stock Exchange. This means that investors who want to buy or sell shares of Company B must do so on that exchange.

The examples illustrate how dual listing works. In the first example, Company A is listed on two exchanges, which gives investors more flexibility in trading the stock. In the second example, Company B is only listed on one exchange, which limits the options for investors.