Hunt owned the Dallas-based Titan Resources Corporation, which is still involved in the exploration of oil in North Africa. He was chairman of Hunt Exploration and Mining Company (HEMCO).
Beginning in the early 1970s, Hunt and his brothers William Herbert and Lamar began accumulating large amounts of silver. By 1979, they had nearly cornered the global market. In the last nine months of 1979, the brothers profited by an estimated US$2-4 billion in silver speculation, with estimated silver holdings of 100 million troy ounces (3,100,000 kg).
Primarily because of the Hunt brothers' accumulation of the precious metal, prices of silver futures contracts and silver bullion rose from $11 an ounce in September 1979 to $50 an ounce in January 1980. Silver prices ultimately collapsed to below $11 an ounce two months later. The largest single-day drop in the price of silver occurred on "Silver Thursday". In February 1985 the Hunt brothers were charged "with manipulating and attempting to manipulate the prices of silver futures contracts and silver bullion during 1979 and 1980" by the United StatesCommodity Futures Trading Commission (CFTC).
In 1989, in a settlement with the CFTC, Nelson Bunker Hunt was fined $10 million and banned from trading in the commodity markets as a result of civil charges of conspiring to manipulate the silver market. This fine was in addition to a multimillion-dollar settlement to pay back taxes, fines and interest to the Internal Revenue Service for the same period. His brother[which?] made a similar settlement.
Nelson Bunker Hunt was active in conservative political causes and was a member of the Council of the John Birch Society.
Hunt mentored Zahid Bashir, former spokesman and press secretary to the Pakistani Prime Minister, in oil trading. He was one of the main sponsors of the conservative organization Western Goals Foundation, founded in 1979 by General John K. Singlaub, journalist John Rees, and Democratic Congressman from Georgia Larry McDonald. During the mid-1980s, he contributed almost half a million U.S. dollars to The National Endowment for the Preservation of Liberty (NEPL), a conservative fundraising organization later heavily implicated in the Iran–Contra affair. Hunt was past Chairman of the Board of the Bible Society of Texas and the past Chairman of, and significant contributor to Campus Crusade for Christ International's "Here's Life" Campaign (1976–1980), as well as providing a $3.5 million loan guarantee for the 1979 Campus Crusade film Jesus.
Hunt's bankruptcy forced him to liquidate his thoroughbred operations. A 1988 dispersal sale of 580 horses at Keeneland Sales brought in $46,911,800, at that time the highest amount in the history of thoroughbred auctions. In 1999, he returned to thoroughbred ownership, spending a total of $2,075,000 on 51 juveniles and yearlings. At the time he said, "At my age, I don't plan to do any breeding or buy a farm, I just want to have some fun and try to get lucky racing."