Square has built its reputation as a quick and simple way for micro-merchants to accept card payments, but the company says it has proven it can serve the more demanding needs of larger retailers.

Payments acquirer WorldPay US is working with Discover Financial Services to allow merchants with brick-and-mortar stores to accept PayPal at the point of sale.

The mega-retailers' Merchant Customer Exchange venture argues that the mobile-payment system it is developing will appeal to retailers in a way no other mobile wallet can. That’s leaving some companies divided on which mobile approach is best—MCX's focus on gaining retailer acceptance or the emphasis on consumer adoption championed by Isis and others.

If Apple Inc. wants to make a strong move into mobile payments, it could do so by transforming its iTunes database into a payment and loyalty program, a recent industry report says.

PayPal Inc., pushing ahead with its drive to become the payment option of choice at the point of sale, has entered an agreement with hardware maker NCR Corp.

"We're open to partnering and playing with the existing networks, but not under the existing rule base," says Jamie Henry, senior payment director of Wal-Mart Stores Inc. "The existing rules that are in place for card-based payments are not going to be acceptable for mobile-based payments."

VeriFone Systems announced Jan. 14 a suite of payment products, including an iPad mini version of its Payware Mobile card reader, a similar sleeve for the iPhone 5 and VeriFone HQ, a cloud-based system that allows retailers to monitor their terminals and manage their brands.

It's been more than two months since Lower Manhattan was engulfed by flood waters from Superstorm Sandy and many merchants are still without the ability to accept credit and debit cards.

It's going to be a big year for mobile payments. Now that several mobile wallets are in consumers' hands, the companies behind them are refining their products. What do Apple, Isis, Google, PayPal and others have in mind for the near future?

ATMs do a lot more now than they did in 2011. They still accept deposits and dispense cash, but today a few also dispense prepaid cards, connect to Facebook, and interact with smartphones. Other types of machines are also treading on ATMs' turf.

Google’s mobile wallet appears to be staggering to the finish line of 2012. After all, it was a year that started with a reported security breach and is ending with speculation that the search-engine giant will add a plastic card to the otherwise entirely digital wallet.

The Google Wallet we see today is a much different product from what we had a year ago. Here are the major changes that took place this year, and the challenges Google faced — and still faces today.

Twitter's immense popularity has caught the attention of many established payment companies and entrepreneurs. Several have attempted to turn the microblogging service into a payment channel, but so far there are few success stories.

Apple introduced its Passbook app — a wallet that stores other mobile wallets — alongside the iPhone 5 in September. Three months later, has Passbook revolutionized mobile payments? Or is it starving from lack of support?

At the heart of many mobile wallets is a system for offering discounts, so these wallets seemed a natural fit for Black Friday shopping. Did they live up to their potential?

This holiday season many retailers are introducing experimental payment technology — but will shoppers, stressed and desperate, find benefit in these experiences or stick to methods they know?

SCVNGR's LevelUp is targeting a broader audience for its mobile-payment system by working with the prepaid card marketer NetSpend. The partnership represents new territory for both companies.

There is no single definition of a “mobile wallet.” Each product differs vastly in its choice of technology, audience and the basic type of payment upon which it was built — but most fit into a few simple categories.

Google has reinvented its mobile wallet a few times, and its latest reinvention, a rumored plastic card, raises questions about the mobile-pay product’s direction.

Many third-party mobile payment providers, such as Google and Isis, are seeking bank partners for their mobile wallets. Should banks agree to their terms or go it alone?