Health savings account programs offer a significant opportunity for banks to increase their deposit base, a new report suggests.

In 2007, HSA assets amounted to only 0.075% of total retail bank deposits, according to Red Gillen, a senior analyst at Celent L.L.C., Boston.

But account acquisition costs ranged from just $100 to $120 for HSAs, compared with about $300 per general retail deposit account acquired, and HSAs have an account closure rate of 12%, compared with an attrition rate of 20% for all retail deposit accounts, Gillen writes in the Celent report.

A bank that registers employers in HSA programs has an opportunity to enroll large groups of employees, even thousands at a time, Gillen writes.

Earlier this year, there were 4 million to 5 million HSAs in existence. Consumers could open 900,000 HSAs this year, and as many as 3.4 million HSAs in 2012, Gillen predicts.

In 2012, he estimates, HSA deposits could total about $27 billion.