Benham joined R.W. Pressprich & Co. in 1934 as statistician and bond analyst.
On March 1, 1934, Isabel Benham joined the bond house R.W. Pressprich & Co. as a statistician and bond analyst. This role marked the beginning of a focus on the railroad industry, an area of finance that needed rigorous analysis. By joining this firm, she not only continued her professional development but also became known for her ability to accurately evaluate the potential and risks associated with railroad investments. Her work at Pressprich & Co. established her as a formidable presence on Wall Street, both as a skilled analyst and as a woman making significant inroads in an exclusively male profession.