What happens when a public company announces they could soon have millions of new customers? Its stock goes through the roof, of course. Such is the case for Apple, one day after announcing an iPhone deal with China Mobile.

At midday, shares of Apple are up over 3 percent. In the last month, the stock is up nearly 9 percent.

On Sunday, Apple and China Mobile announced a multi-year deal that will bring the iPhone to the world’s largest carrier for the very first time. Beginning Jan. 17, China Mobile’s 780 million subscribers will have a chance to purchase the iPhone 5s and iPhone 5c. Preregistration from the company’s official website begins on Wednesday, Dec. 25.

In announcing the news, Apple CEO Tim Cook notes:

Apple has enormous respect for China Mobile and we are excited to begin working together. China is an extremely important market for Apple and our partnership with China Mobile presents us the opportunity to bring iPhone to the customers of the world’s largest network …

… iPhone customers in China are an enthusiastic and rapidly growing group, and we can’t think of a better way to welcome in the Chinese New Year than getting an iPhone into the hands of every China Mobile customer who wants one.

China Mobile has over 1.2 million 2G/GSM, 3G/TD-SCDMA, 4G/TD-LTE base stations and over 4.2 million Wi-Fi access points. By the end of 2013, the company’s 4G services will be available in 16 cities including Beijing, Shanghai, Guangzhou, and Shenzhen. By the end of next year, China Mobile plans to complete the rollout of more than 500,000 4G base stations, which will cover more than 340 cities with 4G service.