Sapient Corp. will enter a marketing alliance with Geezeo Inc. to improve the accuracy of its targeted ads.

"Online marketing is fundamentally grounded in the quality of the data you have and the ability to serve up relevant messages based on that data," said Alex Sion, Sapient's vp of digital strategy and financial services.

The alliance will allow banks to incorporate data from Geezeo's personal financial management tools into the Boston vendor's BridgeTracker marketing platform, Sion said.

BridgeTracker is used by large financial institutions to target online and e-mail ads to their customers, typically using the financial institution's own data as well as the customers' online surfing history. With the addition of data from Geezeo, financial institutions also would be able to see spending, saving and research trends from beyond their own Web sites.

As part of the deal, Sapient agreed to sell Geezeo's technology to BridgeTracker clients and Geezeo will sell BridgeTracker to its clients. Since the companies typically serve financial institutions of vastly different size, this would make both technologies available to new markets, Sion said. He said that although no customers have signed on to use both products, the companies have been in discussions with clients.

Geezeo, of Tolland, Conn., a provider of budgeting tools for consumers, has been reshaping itself as an online banking provider and said that deals such as the one with Sapient are key to its being able to provide a complete set of services to current and prospective clients.