Eidos Montreal’s referencing the letter T as their next big game, has brought up speculation that the company is working on Thief 4. To quote: “Eidos-Montréal is proud to announce the recruitment for our 2nd ‘AAA’ project. … A hint! The title begins with the letter ‘T'”, the studio’s teased on its website.
Obviously Eidos has other IPs beginning with the letter T, but according to CVG a new Thief sequel is most likely because the Eidos Montreal studio is currently developing Deus Ex 3. This is significant, because both game series have a linked history, namely that Thief: Deadly Shadows and Deux Ex one and two were being previously handled by Eidos’ Ion Storm studio which closed for good in 2005.