BAA has saved £300m ($443m) this year by making changes to its procurement process as part of its 2008-2013 five-year programme.
BAA capital director Steven Morgan said programme measures included tendering work outside the framework, cash rewards for good performance and slashing red tape.
In January 2009, BAA was £300m over its £4.1bn ($6bn) spending limit, however the company has saved nearly £260m ($384m) by undertaking the above changes and by cancelling other projects.
The nine primary contractors previously allocated projects under the framework will now have to compete for up to £20m ($29m) of work, while larger projects are being offered to the market.
Contractors include Balfour Beatty, Carillion, Costain, Ferrovial Agroman, Laing O'Rourke, Mace, Morgan Ashurst, Skanska and Taylor Woodrow.