Apple is reported to have already inked deals with American Express, MasterCard and Visa for a digital payment system for iPhone 6, to be unveiled on September 9.
Baird analyst Colin Sebastian issued a note calling Apple's rumored "iWallet" the "elephant in the room," noting that, "while there is no shortage of competition in payments, we view Apple as perhaps the most legitimate potential threat to PayPal's strong position."
The market for mobile payments is expected to reach $1 trillion worldwide by 2017, according to data from IDC.
Among other recent entrants, including Amazon, Google and eBay, Apple "has a strong base of existing customers that it could leverage for mobile payments," Sebastian observed. Apple now has more than 800 million iTunes accounts, most of which are tied to credit cards.
"We believe Apple's closed-platform, software expertise, and brand power position it well," Sebastian wrote. "Additionally, integration with its anticipated wearable device could be a key feature. We believe mobile payments could be a significant opportunity."
"We view Apple as perhaps the most legitimate potential threat to PayPal's strong position" - Baird analyst Colin Sebastian
In addition to having lots of active iTunes and App Store accounts, Apple's customers also represent the most valuable segment of buyers.
Despite vast "market share" volumes of Android users, IBM announced last year that Apple's iOS was being used to do the most mobile shopping by a wide margin, from the important American Thanksgiving Black Friday throughout the Christmas holiday season.
Analyzing terabytes of data from 800 retail sites, IBM reported that iOS devices accounted for more than five times the total sales of Android devices. The firm also said that iOS users spent an average of twice as much per order.
IBM subsequently entered into an exclusive partnership with Apple to use the new Swift programming language to develop over 100 custom apps targeting the needs of enterprise users in specific markets.