Shares of International Business Machines (IBM) fell 5% on Wednesday, April 19, after the company posted a disappointing first-quarter earnings report.

Legendary investor Warren Buffett took a big hit from IBM’s decline. His investment conglomerate Berkshire Hathaway (BRK-B) is IBM’s largest shareholder.

At the end of 2016, Berkshire held 81.2 million shares of IBM, good for 8.5% of the company’s share count. Berkshire’s investment is worth approximately $13 billion. IBM is one of Buffett’s highest yielding holdings. After the 5% decline, Berkshire’s investment in IBM lost roughly $800 million in value. 

IBM is a high-quality dividend stock. It is a Dividend Achiever, a group of 265 stocks with 10+ years of consecutive dividend increases. You can see the full Dividend Achievers List here. With four more years of dividend increases, IBM will join the ranks of the Dividend Aristocrats, a group of companies in the S&P 500 that have raised dividends for 25+ years.

Despite the one-day drubbing, Buffett likely has no intention to sell IBM—and neither should you.

Business Overview

IBM’s recent stock price decline stems from its first-quarter report. IBM reported adjusted earnings-per-share of $2.38, on $18.16 billion of revenue. Adjusted earnings-per-share beat expectations of $2.35, but revenue fell short by about $230 million. On a year-over-year basis, first quarter revenue declined 3%, while adjusted earnings-per-share increased 1%.

Cost discipline helped the company exceed earnings-per-share estimates. But investors seem to be focused on IBM’s revenue. Not only did it miss estimates, this past quarter represented the 20th in a row of declining revenue for the company.

IBM’s turnaround is fueled by growth in what the company calls its “strategic imperatives”. These include big data, security, mobile, analytics, and the cloud. IBM believes there is a huge market opportunity across these areas.