Alibaba Group Holding Ltd (NYSE:BABA)’s initial public offering is one of the most highly anticipated ones this year, and the company has several different businesses.  Two of the company’s online properties are Tmall and Taobao. Sanford Bernstein analysts Carlos Kirjner and Peter Paskhaver have examined both properties. They published their analysis in a report dated Sept. 17, 2014.

How Alibaba's Tmall and Taobao Affect Overall Results

Alibaba’s Tmall data explained

The Bernstein team examined data from YipitData and other datasets to give investors a clearer picture of these parts of Alibaba’s business. They found that services are already a major part of Tmall’s gross merchandise volume, making up approximately 25% of it in the second quarter.

Within the services, they say mobile services like prepaid minute refills are the biggest category in the second quarter. The analysts estimate that China Mobile had the biggest Tmall store according to gross merchandise volume in the second quarter.

So what does this mean for Alibaba? They say that if the Chinese online retailer is able to expand the portion of the “services wallets” it currently captures by a lot, it could see “significant growth” in overall gross merchandise volume and also gross merchandise volume per user. That’s even though they expect an influx of lower disposable income users in the future.

Alibaba’s Tmall volumes appear “highly concentrated”

The Bernstein analysts also say that it looks like the top .1% of Tmall stores according to gross merchandise volume made up approximately 30% of the overall gross merchandise volume in the second quarter. They say this high concentration level appears in most of the various categories.

They believe the joint Tmall – Taobao marketplace remains the most efficient way for major brands and retailers to pull in traffic. They believe that the risk of any large amount of defection remains small over the next couple of years as well.

However, they think the high concentration of gross merchandise volume means that there is a long term risk of major sellers defecting if alternative traffic acquisition strategies emerge. For example, they could build up their brands and create their own standalone sites, taking their loyal customers with them when they leave Alibaba’s marketplaces.