The US-based practice is working with Gillespies and is up against Gustafson Porter, which designed the Diana Princess of Wales memorial fountain.
The shortlist includes a team led by France’s Agence Ter, the creative force behind Les Halles in Paris, jmarchitects, John McAslan & Partners and Burns + Nice. The latter firm recently overhauled Leicester Square.
Client Glasgow City Council is calling on designers to "create a George Square fit for the 21st century" by entering a competition but has had to delay the competition several times to clarify procurement issues.
"Over the years the square has had a number of adjustments but is no longer the grand civic space it once was," said a spokeswoman of the project create a space of "outstanding design quality".
The proposals would see 13 monuments temporarily relocated to other parts of the city and the square’s distinctive red tarmac torn up and resurfaced. Building work is due to start next April.
Council leader Gordon Matheson said: "It is time for George Square to regain its status as not only Glasgow’s premier urban space but Scotland’s premier urban space. There are competing demands which are placed on the square.
"This year alone George Square has hosted the Queen on her diamond jubilee tour as well as the Olympic torch and will be the focal point for the homecoming of Scotland’s Olympians and Paralympians. People also use it as a place to sit around watching life pass by.
"Currently it is not equipped to perform either of those roles particularly well. We need to be more ambitious and have implemented an ambitious programme of work including a wide-ranging consultation with the public and stakeholders."
George Square was laid out in the 1780s, originally as a private, enclosed garden for surrounding houses. The garden square was gradually been given over to public use and became a focus over the years for civic celebration and public dissent.
The project forms part of the Buchanan Quarter tax increment finance scheme, which aims to lever in £310m of private sector investment including up to £80m for public infrastructure works and public realm improvements.