These delegates have signed a letter to the Financial Times calling for Britain to remain in the EU.
The heads of 15 major international companies, including GE, Cisco, Mars, EMC, Airbus, and former New York Mayor Michael Bloomberg, have signed a letter to the Financial Times calling for Britain to remain in the EU.
Representatives from many of the companies, which the government said together employed more than 170,000 people in Britain, also met Prime Minister David Cameron on Thursday to discuss Britain's June 23 EU membership referendum.
"We see Britain's EU membership as a win-win situation: the single market offers us seamless access to a market of 500 million people, giving us instant possibility to scale up our investment," the business leaders said in the letter, published in the newspaper on Thursday.
Jeff Immelt, chief executive of GE; Tom Enders, chief executive of Airbus Group; Chuck Robbins, chief executive of Cisco; Hiroaki Nakanishi, chairman of Hitachi Ltd and Grant Reid, president of Mars, among others, signed the letter.
The signatories said if Britain were to leave the single market, major international businesses' future investment decisions could be affected.
A spokesman for Cameron said that during Thursday's meeting, many of the companies said they had located their European headquarters in Britain knowing they would have free access to the EU's single market.
Concerns were also voiced at the meeting about the uncertainty that would be caused by a vote to leave, he said.
"The prime minister and others (made) the point that it could take much longer than two years to settle the UK's trade relationships outside the EU, and that uncertainty would cause enormous damage to UK inwards investment," he said.
"There was also concern voiced about the impact on the supply chain, with several business representatives pointing to the huge number of small and medium-sized businesses involved in their supply chain that would be affected by a vote to leave."
Those attending the meeting included Siemens UK Chief Executive Juergen Maier, IBM's UK and Ireland Chief Executive David Stokes and Ford Executive Vice President Jim Farley, the government said.
Microsoft said on Tuesday that Britain should stay in the European Union if it wanted to get more investment, while Ryanair said last week it would withdraw some investment if Britain opts to leave the EU.
Sterling hit a three-month high against a trade-weighted basket of currencies on Wednesday, after a poll gave an 18-point lead to supporters of Britain staying in the EU.
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