The chairman and chief executive of Target resigned Monday following steps taken by the major corporation to rebound from last year's massive data breach that exposed costumer information.

Gregg Steinhafel, who had been chief executive for the company since 2008, is resigning after being with Target for a total of 35 years, The New York Times reports. The decision was made after the company board decided it wanted new leadership.

Target said it would conduct a search for Steinhafel's successor. In the meantime, John Mulligan, Target's chief financial officer, will serve as president and chief executive. Roxanne S. Austin, a Target board member, will be non-executive chairwoman.

"The last several months have tested Target in unprecedented ways," Steinhafel said in a letter to the board. "We have already begun taking a number of steps to further enhance data security, putting the right people, processes and systems in place."

Last week, Target announced that it will adopt chip-and-PIN technology for all in-house debit and credit cards, which is a service that is used in Europe and is considered to be more secure. The company estimates that the switch to the new technology could cost around $100 million. Target also said it spent $61 million in its fourth-quarter expenses on "breach-related expenses."

There have also been data breaches at other stores as of late, most notably at Neiman Marcus and Michaels. Those involved in the investigations say the breaches were most likely performed by the criminals who breached Target's system, who are cyber criminals from Eastern Europe.

Target also has other issues in addition to the company's costly damage control strategies. The company recently opened more than 100 stores in Canada in the last few months, which have delivered disappointing profit margins. Target has also struggled with inventory issues.

Retail analysts say that Steinhafel's resignation is not a good sign for the company.

"Presumably the board was not pleased with Steinhafel's performance, and we think that it is fair to assume that current business trends are not particularly good," Faye Landes, an analyst at Cowen, wrote to investors. "The board also may have come to the conclusion that the problems leading to the credit breach were the results of underinvestment, which is a C.E.O. decision, and the aftereffects of the breach may ultimately be quite costly, which we believe to be the case."

The company's stock dropped in January and February following the massive credit card burglary.

In late December, the breach exposed the payment information of 40 million Target customers, and the personal data of an additional 70 million. Twelve million people are believed to have had their payment and personal information compromised.

Target also said there were signs of computer hacking that were not investigated preceding the breach.

Following the breach, the company has been scrutinized by security experts, and Target officials have been summoned to testify before congress about customers' privacy on the Internet.

The company's chief information officer at the time of the breach, Beth M. Jacob, resigned shortly after the crisis, and officially stepped down in March. Target announced last week that she will be replaced by Bob DeRodes, a technology expert who formerly held positions at Delta Air Lines and Home Depot.