In the early 19th century Germany consisted of many independent states, most of which issued their own, differing coinages; young Joseph made a profit at his mother's shop changing money for travelers for a small fee.

In particular, migration of the peasant class (Seligman's father's customers) from rural to urban areas meant a loss of job opportunities and a shrinking economic base in Baiersdorf.

[4] Along with Jacob H. Schiff, H. B. Claflin, Marcellus Hartley, and Robert L. Cutting, he was a founder of the Continental Bank of New York in August 1870.

[5] During the American Civil War, Seligman was responsible for aiding the Union by disposing of $200,000,000 in bonds "a feat which W. E. Dodd said was 'scarcely less important than the Battle of Gettysburg'".

According to Stephen Birmingham, Seligman was obliged to accept "7.30 bonds" from the government as payment for the uniforms his factory was delivering.

Union defeats, combined with a suspiciously high interest rate, lowered confidence in the bonds, making them difficult to sell.

& W. Seligman & Co. invested heavily in railroad finance, in particular acting as broker of transactions engineered by Jay Gould.

[8] In 1877, Seligman was involved in the most publicized antisemitic incident in American history up to that point, being denied entry into the Grand Union Hotel in Saratoga Springs, New York, by Henry Hilton.

In 1877, President Rutherford Hayes asked Seligman, August Belmont, and a number of other New York bankers to come to Washington, D.C., to plan a refinancing of the war debt.

In 1877, Judge Henry Hilton, the owner of the Grand Union Hotel in Saratoga Springs, New York, denied entry to Seligman and his family because they were Jews, creating nationwide controversy.

During the 1870s, several incidents made Alexander Stewart hostile towards Seligman, although the two men had served together on the board of the New York Railways Company, whose president was Judge Henry Hilton, a Tweed Ring associate.

The estate included a two-million-dollar stake in the Grand Union Hotel in Saratoga, as well as A. T. Stewart's department store on Astor Place.

[11] After helping refinance the war debt in Washington, D.C., Seligman decided to vacation with his family at the 834-room Grand Union Hotel in Saratoga Springs, New York, where he had stayed before.

The New York Times, on June 19, 1877, ran a headline set entirely in capital letters:[12] A month later, The New York Times disclosed a letter in which Judge Hilton told a friend, "As [yet] the law ... permits a man to use his property as he pleases, and I propose exercising that blessed privilege, notwithstanding Moses and all his descendants object.

A group of Seligman's friends started a boycott against A. T. Stewart's, eventually causing the business to fail; a sale to John Wanamaker followed.

[14] This prompted Hilton to pledge a thousand dollars to Jewish charities, a gesture mocked by the satirical magazine Puck.