NI's leaders are on a five-day visit to America in a bid to strengthen business and tourism links with the country and on Wednesday the Ministers took their sales pitch to some of the world's biggest technology firms.In an effort to boost the network of contacts and attract potential US investors, the NI leaders opened an Invest NI office in the city.The San Francisco team will focus on increasing NI's presence within high technology sectors across America."Operating costs in Northern Ireland are on average 20% to 30% cheaper than in the rest of the United Kingdom and Western Europe which, in the current financially challenging environment, is a major consideration for companies," Mr Robinson said."We reinforced why Northern Ireland is one of the most competitive business propositions in Europe due to our transport links, telecommunications infrastructure and the skill base of our people."The DUP leader added: "West Coast companies such as Cybersource, Visa, Vello Systems and WANdisco have already brought much-needed jobs and investment into Northern Ireland. Through events like this we hope to convince many more businesses of the benefits of choosing Northern Ireland as a place to invest."6.30am & leaving San Francisco for Washington DC.Excellent engagement y'day with 120 senior Executives & Business people in Silicon Valley.— Martin McGuinness (@M_McGuinness_SF) March 12, 2014Mr McGuinness commented: "If you don't travel to the US and meet Senior Business Executives you simply don't count. This meeting enabled us to market and promote the north of Ireland and explore the potential for trade."Visits like this are not only about helping attract investment, but also to support local businesses to develop export opportunities. The US and wider Americas are an important export market for businesses in the north of Ireland, and it is very important that we help maintain strong links to support them to win new business here.The Sinn Féin MLA added: "We have a talented labour force with a very strong work ethic and are well placed to meet international business needs. The retention of existing investors is as important as attracting new investors. Reinvestment by global companies sends a strong signal to the world and is an excellent endorsement of our people."On Tuesday, the Ministers posed alongside Holywood actress Courtney Cox as they attended a Cinemagic showcase in Los Angeles. They will also be making their way to Washington as part of their trade mission.