The bank had said several months ago that it would sell off non-core assets in an effort to bolster its balance sheet.
"Advent has a long and impressive record of investing in and growing payment processing companies to achieve exceptional results, and we believe that its investment will significantly enhance the ability of our processing business to generate even stronger results in the future," said Kevin T. Kabat, CEO of Fifth Third Bancorp in a statement about the sale.
"Partnering with Advent will provide the processing business with access to additional capital and resources that we believe will create significant new opportunities and incremental growth in that business."
He added, "This transaction represents the culmination of work we began last summer as part of our capital plan announced in June. It is expected to generate meaningful additions to our tangible common equity and Tier 1 capital ratios, reflecting the value of the business as a whole, while at the same time enabling us to retain significant ownership in the joint venture and its ongoing creation of value."