The firm secured a spread of 16 projects together valued at around £516m and strengthened its grip on the 12-month rolling league compiled by Barbour ABI where it has held pole position since April.
Kier has now accumulated double the value of work of its closest rivals: Wates, Bam and Morgan Sindall.
Its major win for the month was HMP Full Sutton, a new £400m category C prison in East Yorkshire with construction set to start this autumn.
Among the other major contracts signed off during the month, Skanska bagged a £450m deal to upgrade a 6.6km stretch of the A46 Newark Bypass in the Midlands.
Skanska will now begin design works and subject to development consent being granted, work on site will start in 2025 for opening to traffic in 2028.
Also on the roads, Volkerwessels secured an £80m deal for junction 10 of the M27, while Graham bagged highways infrastructure for the 4,600 homes Milton Keynes East extension.
Buckingham Group took two major shed units at Kettering South Symmetry Park in Northamptonshire, while A&H secured a major shed project at Griffin Park, the former Neovia site in Leicestershire.
Bowmer & Kirkland benefitted from Whitehall’s levelling up drive securing an £80m deal to build a new £80m regional HQ for HMRC on Pilgrim Street in Newcastle (above).
Morgan Sindall’s Overbury business also secured a £70m job to fit out 10 floors at the 1 Padding Square new office block in London (above).