The DUP and Sinn Fein have agreed that the new rate for corporation tax in Northern Ireland should be 12.5%.
First Minister Peter Robinson unveiled the figure during his historic appearance at a business breakfast in west Belfast yesterday morning.
The two parties have made the deal to try and get the powers to set the tax rate pushed through by St Patrick's Day when the First and Deputy First Ministers are flying to America to promote investment here.
"We need to have the dates and the rates to show the Americans, that is the most important thing," one DUP source said.
Just days ago the DUP had argued for a rate of 10% to undercut the Republic's 12.5%.
In the UK the tax is charged at 21% but that may soon fall to 20%. Mr Robinson said 12.5% was emerging as the consensus.
Corporation tax is charged on business profits and the Republic's low rate has been credited with attracting in blue-chip US companies like Amazon and Google.
Each percentage point cut will cost us about £40m a year from our block grant, though the final figure has yet to be disclosed.
The Executive parties believe the investment is vital to revitalise the economy. The London Government has agreed to pass the legislation in April before the election, allowing the powers to actually go live in about two years.
In the meantime the Executive and Invest Northern Ireland intend pitching the new rates to potential US investors to tempt them in.
Mr Robinson described yesterday's event, which was chaired by West Belfast Sinn Fein MP Paul Maskey, as "an historic first".
He added that he believed such visits from unionists to the republican constituency should become "the new norm".
Mr Robinson's best-known previous engagement in the constituency was in 2012 when he attended a special GAA event in Casement Park called Match for Michaela, in memory of Michaela McAreavey, the murdered daughter of Tyrone football manager Mickey Harte.
Yesterday he was accompanied by his party colleague, Enterprise Mininster Arlene Foster.
The DUP duo was welcomed and Mr Robinson said he was as just as enthusiastic about bringing jobs to west Belfast as his own constituency.
Mr Maskey welcomed them with a few words of Irish "I extend a 'céad míle fáilte romhaibh' to you Peter and Arlene and all at this morning's event on behalf of the people of west Belfast," he said.
He added: "Your presence here sends a very important message to all the people of this area... This is the First Minister and the Minister for Enterprise and Investment coming into the heart of west Belfast.
"I have no doubt that people will be asking them for further assistance and, obviously, hoping that government steps up to the mark even further in the future."
The breakfast was hosted by Gerry Carlile, the west Belfast-born football scout and entrepreneur.
"If we can advance the economy and create jobs, then we can also advance the peace and make sure that the standards of people's lives are better than what they have been in the past and what they currently are," he said.