The stock sagged almost 5% after IBM reported a bigger-than-expected 2.6% fall in revenue for the three months to March.
It was the 20th consecutive quarter that revenues for "Big Blue" had declined.
The fall dragged the Dow Jones down 0.6% to 20,404 points at the close - its lowest level since February.
The broader S&P 500 also fell 0.2% to 2,338.1 points, but the tech-focused Nasdaq rose 0.2% to 5,863 points.
Twenty-First Century Fox fell 0.8% after Fox News severed its relationship with Bill O'Reilly, dumping America's most-watched cable news presenter after a flood of sexual harassment allegations and an advertiser boycott.
Morgan Stanley rose 1.9% after reporting a 75% rise in first-quarter profits on strong trading results.
Poor quarterly results at IBM turned the company into the biggest loser on the Dow Jones on Wednesday.