Any marketing consultant will tell you that one of the best ways to increase sales is to market to existing clients. They already have a relationship with you and - presumably - trust you. Consequently, they should be easy targets for cross-selling or up-selling. Call it low-hanging fruit. Financial marketers even have a fancy (if somewhat dull) name for it: increasing share of wallet.

For large banks that are approaching the cap on deposits that can be reached through mergers and acquisitions, cross-selling becomes an even more important marketing strategy. It is surprising, then, that we are seeing little use of one of the best channels to reach a captive audience: the bank's private (or customer) website.

In our latest Bank Monitor report, Private Site Cross Promotion: selling old clients something new, we looked at how the major banks are using their customer sites to promote additional products and services to their clients. Some interesting findings:

In our research, we found two firms that stood out in using their customer sites to cross-sell services: Bank of America and Citibank. Both firms offer pages of special offers for users that provide specific account details, and both offer a separate Apply page to prompt users to open new accounts.

Over the years, banks have become adept at using "traditional" media to cross-sell to clients (e.g. statement inserts, bangtails, etc.). It is important not to forget the online channel in these efforts.