Animal testing group Huntingdon Life Sciences had its planned New York Stock Exchange (NYSE) listing pulled just 45 minutes before it was due to go ahead.
Huntingdon bosses were reportedly taken aside by the NYSE's president
Executives from the UK research group were taken aside by the exchange's boss and told the listing had been halted.
The NYSE is reported to have received calls warning that the exchange could be threatened by animal rights activists opposed to the firm's debut.
Huntingdon quit the London Stock Exchange in 2001 after fierce protests.
The company moved its headquarters to the US after a sustained - and often violent - campaign by animal rights protesters in Britain.
Shares in Life Sciences Research, the US parent company set up by Huntingdon, had been due to start trading on Wednesday.
Huntingdon's boss said he was puzzled by the NYSE's decision
According to reports, Huntingdon chief executive Brian Cass was taken aside by NYSE President Catherine Kinney on the trading room floor and told that the listing had been halted.
"Obviously we were greatly disappointed," Mr Cass told the BBC.
"There have been threats from various aspects of the animal rights movement both in the UK and the United States, but whether that is the issue or not, it is something the exchange must answer."
Investors in New York also expressed surprise that the US exchange had apparently caved-in to pressure from protesters, although one activist group described the move as "another slap in the face" for Huntingdon.
A spokesman for Huntingdon said the company's day-to-day operations would not be affected by the sudden pulling of its New York listing.
"It's not the first time we've been at the centre of a storm," he said.
Activists have protested against a number of companies involved in animal testing in recent years, targeting shareholders and businesses connected with laboratories.
The UK-based Stop Huntingdon Animal Cruelty campaign focused its efforts on Huntingdon's suppliers, many of which eventually severed their ties with the company because they feared getting bad publicity.
The government has since said it plans to clamp down on animal rights activists intimidating company employees, shareholders and suppliers.
Despite the decision by the NYSE, trading in Life Sciences Research continued on the US Nasdaq index's electronic over-the-counter market.