Hundreds of banks are queuing up to join Apple’s newly launched mobile payment system to ensure that customers don’t decide to switch banks just because their credit and debit cards are not working on the iPhone 6 or iPhone 6 Plus they just bought.

According to industry executives, the rush began the moment the Cupertino, California-based company announced Apple Pay. When announcing the service in September, the tech giant did include top banks in the United States and leading credit card networks such as American Express Co., MasterCard Inc. and Visa Inc. However, for the majority of the smaller lenders, announcement of this new service was a big surprise.

In a statement issued on Thursday Apple informed that according to current numbers, Apple Pay has over 500 financial institutions as its members. So, a large number of people using the new iPhones will be able to use the service of their bank on Apple Pay when it will be released in the United States on Monday, October 20.

MasterCard has most likely played a big role is making so many financial institutions a part of Apple Pay. In a recently issued statement, the financial services corporation said that it has been working to ensure that more financial institutions join Pay.

So, what Apple Pay actually is? Apple Pay is a mobile payment system that will allow users to make purchases without using their plastic cards. With this system, users will be able to store their card data on their smartphones. When making payments at cash registers, users will only need to tap the device to the credit card terminal; when making online purchases, on the other hand, users will need to tap the merchant application on their phone.

For now, Apple has made the new payment service available only on its upcoming smartwatch (the Apple Watch) and the two iPhones released last month. However, there are strong possibilities that we will see the feature being added to more Apple products in the near future.

When the system will finally be released on Monday, we will not only see big card issuers such as Bank of America Corp. and J.P. Morgan Chase & Co. offering it; all kinds of financial institutions ranging from smaller organizations to regional banks will be offering this new payment service. According to information provided by Apple, the banks that have already joined Apple Pay represent as much as 83% of all credit-card purchases made in the US.

Having so many banks and other financial institutions as its members, right from the beginning will allow Apple Pay to have a strong start as a payment service provider.