BDO USA, LLP

An era of expansion began. Fostered by the federal government's conversion of furniture and woodworking companies to aircraft production for the war effort, the firm opened an office in Grand Rapids, Michigan, in 1917. Seidman and Seidman quickly established itself as a leader in serving the furniture industry by developing the first effective furniture plant costing system. Today, BDO Seidman's furniture industry practice remains in the industry.

In 1925, the firm rapidly expanded, opening offices in Jamestown, Illinois, and Rockford, Illinois, followed by Chicago in 1921, and Gardner, Massachusetts, in 1924. In 1922, J. S. Seidman joined the firm as a founding member.

The 1930s brought another new beginning for the accounting profession. In 1933, Congress passed the Securities Act, requiring public corporations to have financial statements included in registration statements and periodic reports reported on by independent CPAs. A year later, the Securities and Exchange Commission was created to administer the new legislation.

In 1950, L. William Seidman joined the firm and ultimately became its managing partner before leaving for government service, most notably as chair of the FDIC.[5]

The firm continued to grow and by the 1960s, truly became a national firm. On April 1, 1968, the firm was converted into a national general partnership. This marked the beginning of a new era of expansion. Over the years to the present, the firm established many offices throughout the United States.

A group of D.C. government employees had embezzled funds by fraudulently issuing real estate tax refund checks to their friends. BDO Seidman was the independent auditor of the D.C. government's financial records. On November 21, 2007, Reuters wrote "Washington, D.C., officials should fix problems identified in an audit that found the city mishandled millions of dollars, according to Delegate Eleanor Holmes Norton, who represents the U.S. capital in Congress ... The audit, conducted by accounting firm BDO Seidman, LLP, found that financial reporting for the city's school system and Medicaid programs did not match their financial statements, making both areas vulnerable to fraud ... Altogether, auditors found more than 160 instances where the city failed to comply with conditions for spending federal money, primarily by misreporting funds and mismanaging cash." As of November 2007, it was estimated that over $30 million were scammed by Washington, D.C. tax officials since 1999. At the height of the scam, half of the property tax refund checks were fraudulent. The average legitimate check was less than $10,000 while the average scam check was over $300,000. "The scandal may also singe BDO Seidman, a private audit firm that gave [Washington D.C. CFO Natwar Gandhi its seal of approval earlier this year. Its auditors were paid millions to go over the city's books and gave Gandhi's office an unqualified opinion." In 2010, a mentally ill woman, who was not a D.C. employee was able to exploit a security loophole in D.C.'s financial systems to file tax returns claiming $19.1 million in refunds, but these were stopped. [9]

On December 16, 2008, in connection with the Bernard Madoff scandal, the New York Law School filed a lawsuit against J. Ezra Merkin, Ascot Partners, and its auditor BDO Seidman, after losing its $3 million investment in Ascot. The lawsuit charged Merkin with recklessness, gross negligence and breach of fiduciary duties.[10]