Updated

The Internal Revenue Service announced Wednesday that Doug Shulman, who has led the agency for more than four years, will step down next month.

Shulman, who was appointed IRS commissioner by President George W. Bush and confirmed by the Senate in March, 2008, will leave the post on Nov. 9. Steven Miller, a 25-year veteran of the agency, will serve as acting commissioner until the president nominates a permanent successor.

As commissioner, Shulman was responsible for delivering about $300 billion, or some 40 percent, of the funds made available in President Barack Obama's 2009 stimulus package to revive the faltering economy.

He has also overseen an offshore tax evasion prevention program under which the agency has been able to collect more than $5 billion in back taxes, interest and penalties.

Shulman has also focused on an initiative to ensure that those working in the tax preparation industry meet high standards of ethics and competency.

At a speech at the National Press Club last April, Shulman said he was a "believer in relentless and myopic focus on priorities," which have included improving the image of the tax agency and making the agency, which employs more than 100,000 people, a better place to work. The IRS, in its biography of Shulman, noted that under his tenure the agency has gone from eighth to third out of the 14 largest federal agencies in a rating of the best places to work.

Treasury Secretary Timothy Geithner, in a statement, said Shulman's "work at the IRS, from fighting tax evasion to modernizing technology, has helped make the nation's tax system more fair, efficient, and effective."

The IRS collects some $2.4 trillion in tax revenues every year.

Shulman had indicated earlier this year that he had planned to step down at the end of his term. IRS commissioners serve for a term of up to five years.