Before a sparse crowd at the Federal Reserve’s first of three public hearings, Capital One Financial Corp. officials defended the proposed purchase of ING Direct as a marriage of simple, traditional institutions that pose no risk to the financial system, but great public benefit.

Yet community groups argued that the credit card giant is simply using the $9 billion acquisition to fuel its card business, which if allowed to grow any larger could destabilize the system.

“Neither Capital One nor ING Direct provides the types of critical financial services the disruption of which could pose significant risk to financial stability in the U.S.,” John G. Finneran Jr., general counsel and corporate secretary for McLean-based Capital One, said at the meeting held at Renaissance Hotel Washington today.

Analysts and regulators have identified credit card securities as the likely trigger for America’s next financial crisis, and Capital One is too entrenched in the segment, said John Taylor, president and chief executive of National Community Reinvestment Coalition.

“Capital One’s business model is not sound,” he said. “In 2005, Capital One told the world that it was moving away from its high-risk monoline strategy ... diversifying its business to a 55 percent credit-card to 45 percent consumer banking ratio. Six years and three banks later ... 75 percent of its income still comes from credit cards.”

Stella Adams, the National Association for the Advancement of Colored People’s housing committee chairwoman in North Carolina, raised concerns that Capital One would expand its subprime credit card lending to the detriment of minority communities, on which the bank has preyed.

Finneran said ING’s deposits will supplement Capital One’s “access to stable, lower cost funding for its diverse and traditional consumer and commercial lending activities.”

It’s unclear exactly which streams of the company’s business will benefit the most from the acquisition, but Capital One has plainly said that it will use the acquisition to fund its purchase of HSBC’s credit card portfolio. The purchase is set to make the bank the seventh largest credit card dealer in the country.

Finneran stressed the ING acquisition, which will make Capital One the fifth largest bank in the country, “will serve as a catalyst for community development, local job creation and economic growth.”

He announced a 10-year commitment totaling over $180 billion in new community development lending and investments, as well as increased lending and services to low- to moderate-income borrowers. Yesterday, the bank announced the merger would result in the createion of 3,600 new jobs.

Banking analysts suspected that the bank would make some gesture toward community organizations to illustrate its commitment to under-served groups.