The deal, which will reportedly raise £60m for taxpayers, will ensure a full restoration of the Grade I-listed building before it is opened to the public for the first time since building work was completed in 1912.
PIC has taken on a 99-year lease for the King Edward VII-commissioned property, subject to conditions and planning permission, and will now lead a team of 20 British companies in the project to open an, as yet, unnamed hotel.
Former investment banker Rafael Serrano, chief executive of PIC, was involved in the opening of the luxury Bulgari Hotel and Residences in Knightsbridge and said previously lost features, such as drawings by the building's designer, would be reinstated in the restoration.
"We are committed to preserving the iconic status of Admiralty Arch and celebrating Sir Aston Webb's historic design, while restoring, modernising and adapting it sensitively for a new use that will sustain its value for future generations," he said.
Proposals for the project will now be submitted for a full public consultation, when details of the hotel including its size and features will be announced, before planning permission is decided.
"We will be working with H.M. Government, Westminster City Council, English Heritage, The Royal Parks and local stakeholders during the planning process. We will deliver the very finest hotel for London, with an unrivalled history and location, while providing maximum security measures to protect surrounding Government buildings and areas of State importance."
The Government will retain the freehold for the ceremonial passage and former offices and residences but PIC will have the option of taking up a 125-year lease before the current proposed lease is granted for an extra fee of £5m.
Minister for the Cabinet Office Francis Maude said the hotel, restaurants and bars would restore the building to its 'former glory'.
"At present Admiralty Arch is not being used and is costing £900k a year to run. Rather than letting it fall into disrepair we are taking action. British specialists will work closely with English Heritage and Westminster Council to bring the Arch back to life. The restoration will bring jobs to London and beyond."