The answer is Paul Rand.
Paul Rand was best known for his corporate logo designs, such as the logos for IBM, Morningstar, ABC, NeXT, Enron, and UPS. He embraced and practiced the Swiss Style of graphic design to come up with these logos. Paul met an already existing IBM logo and made it subtle. He replaced the font Beton with a typeface called City and gave the letters IBM a more solid and balanced appearance.