Dual-listing refers to the process of listing a stock on multiple stock exchanges. This is done for a variety of reasons. It increases liquidity, provides more avenues to raise capital, and potentially allows for more trading time if the exchanges are open at different times.
Let's go over how dual-listing works, why a company would do it, and a few well-known examples.

How dual-listing a security works
The most common way a company dual-lists on U.S. stock market exchanges is through an American depositary receipt (ADR). ADRs hold the foreign shares in a trust account and grant U.S. investors the same rights and upside potential.
ADRs trade on the main two U.S. exchanges, the Nasdaq and the New York Stock Exchange (NYSE). They can also trade on over-the-counter (OTC) markets.
For most ADRs, you can purchase the stock in your online brokerage account as you would any other stock. Some may require a limit order if they trade OTC.
Foreign businesses can choose to list on multiple exchanges without using depository receipts but would likely be required to restate financials and follow stringent U.S. Securities and Exchange Commission (SEC) rules on top of the laws of the business's home country.
Generally, the price of a dual-listed security is the same (adjusting for currency differences) on both exchanges where it's listed.
Securities
Pros and cons of dual-listing
The pros, as outlined above, are access to capital with new stock offerings and more stock trading volume.
The cons are mostly related to cost. Listing on multiple exchanges comes at a price. The custodian bank holding the trust when a company goes the ADR route has to be paid, and the entity needs to be structured and updated by lawyers. If the business doesn't dual-list via an ADR, there will be massive costs to state financials under SEC regulations and comply with all other exchange rules.
Institutional Investor
Additionally, when the company is taking advantage of a stock trading on multiple exchanges by issuing more shares, the management team will need to travel to those locales. In the U.S., it is customary to do a road show presenting to institutional investors to drum up interest in the stock offering. Foreign companies may find it beneficial to hold multiple shareholder meetings as well.
All in all, the cons of dual-listing are likely immaterial to multinational corporations looking to raise hundreds of millions or even billions of dollars.
How does dual-listing affect stock price?
On a micro level, dual-listing does not affect stock prices. The prices on the different exchanges will be the same when you account for currency differences and transaction costs.
Over time, having a more liquid stock and the ability to raise more capital for growth could help the stock price go up — but that would only occur if the fundamentals of the business were also getting better.
Related investing topics
Conclusion
Dual-listing is a big plus for U.S. investors because it makes it a lot easier to invest in businesses based in foreign countries. Outside of that feature, it likely won't significantly affect the stocks that you buy over the long term.