Who was Scrooge's business partner in 'A Christmas Carol'?

Jacob Marley

Jacob Marley (who died on December 24, 1836) is a fictional character whose ghost appears in the Charles Dickens novel, A Christmas Carol.

In life, Marley was the business partner of Ebenezer Scrooge. As teenagers, both men had apprenticed in business and met as clerks (presumably in accounting) in another business. The firm of Scrooge and Marley was a nineteeth century financial institution, probably a counting house, as Marley refers to their offices as 'our money-changing hole'. They have become successful bankers, with seats on the London Stock Exchange; they are also stockholders and directors of at least one major association, but a vast amount of their wealth has been accumulated through usurious moneylending.
https://en.wikipedia.org/wiki/Jacob_Marley