Bill Gates Now Ecolab’s Biggest Shareholder

The Microsoft Corporation co-founder holds 11.4 percent of Ecolab's stock.

Bill Gates, through his investment firm, Cascade Investment, bought 3.9 million shares in Ecolab, Inc., this week, according to a report by the Star Tribune.

This latest investment makes Gates the largest stockholder in the St. Paul company, adding to his previously acquired holdings.

Kirkland, Washington-based Cascade Investment reportedly acquired the shares for $189.6 million. Cascade now holds more than 22 million shares worth about $1.1 billion.

Gates also holds about 4.4 million Ecolab shares through the Bill & Melinda Gates Foundation. The combined holdings of the foundation and Cascade amount to an 11.4 percent stake in Ecolab.

Cascade began buying Ecolab shares in late 2010 and in June, held 6 percent of the company's stock. According to a report by the Pioneer Press, Cascade increased its stake when Ecolab in July announced plans to buy Naperville, Illinois-based Nalco, a water treatment provider, for $5.4 billion.

Ecolab reported about $6.1 billion in 2010 sales. It offers cleaning, sanitizing, food safety, pest control, and infection prevention products and services to foodservice, food and beverage processing, health care, and hospitality markets in more than 160 countries.