Few spend 49 years working for the same company. And fewer still do so at an investment bank.

But Eric Dobkin, among the longest-serving partners at Goldman Sachs, achieved that distinction, as the company announced his retirement on Wednesday.

Mr. Dobkin, age 73, is known by many as the father of the modern-day initial public offering of stock. In 1985, he created the firm’s equity capital markets division, which changed the way I.P.O.s were conducted by focusing on mutual funds rather than individual investors. It was a pivot that put Goldman Sachs in the forefront of some landmark deals, including Britain’s largest privatizations and Microsoft’s initial offering.

“Eric’s passion, creativity, market judgment and trusted advice have helped the firm and our clients tremendously,” Lloyd C. Blankfein, the chief executive of Goldman Sachs, and Gary D. Cohn, the bank’s president , said in a memo to the company on Wednesday.

After graduating from Harvard Business School, Mr. Dobkin joined Goldman Sachs in 1967 in the institutional sales group in Philadelphia. Seven years later, he was transferred to Chicago, and then to New York, and he made partner in 1982. When Goldman Sachs went public in 1999, Mr. Dobkin stayed at the company, despite the windfall of cash that the partners received at the time.