LISBON, Portugal — Americo Amorim, known as the King of Cork for building his fortune on cork stoppers and believed to be Portugal’s wealthiest man, died Thursday, his company said. He was 82.

Amorim’s fortune was recently estimated by Forbes at 4.4 billion euros ($5 billion). His company, Corticeira Amorim, is the world leader in cork production. Portugal is the world’s largest cork producer, accounting for about half of global output.

With plastic stoppers for wine bottles encroaching on his market, Amorim diversified cork uses into areas such as insulation and furniture.

He created a conglomerate, Grupo Amorim, which expanded his business into wine production and tourism. Amorim also held significant stakes in Portuguese financial, telecom and energy companies.

His company said he had died but did not immediately provide further details. He stepped down from his executive duties in October due to health problems.

Amorim was the fifth of eight children born to a modest family in the town of Mozelos, in northern Portugal, in 1934.

At 18, he started work at the small cork company founded by his grandfather in 1870. He left that job to spend more than four years traveling through South America, Europe and Asia — a trip he later described as “a fantastic university.”

He inherited a 2.5 percent share in the family cork company and from that he built his business empire on the back of an export drive.

After an army coup in 1974 toppled Portugal’s long dictatorship, many businessmen fled the country. Amorim stayed and bought their assets, sometimes for knockdown prices, including vast areas of cork forest in southern Portugal.

The cork oak is remarkable for its spongy bark, which can be peeled away every nine years or so without killing the tree. Portugal’s cork industry employs around 15,000 people, either working on harvest or in factories making stoppers and other products.

Amorim’s companies do business in dozens of countries around the world. “I don’t consider myself rich. I’m a worker,” he told a Portuguese newspaper in 2011.

He is survived by his wife, three daughters and grandchildren.