Initially developed for executive cars, the architecture was expanded for larger model lines, sports sedans, and multiple body styles.

The Sigma platform uses four-wheel independent suspension with front control arms and a rear multi-link configuration.

Remaining exclusive to the Cadillac division, the design adopted a greater degree of parts sharing with the Australian-designed Zeta platform.

Sigma II became exclusive to the CTS, as the SRX was downsized for 2010, adopting the Theta Premium architecture and the STS was retired after 2011 (the SLS, 2013) with no direct successor.

For 2011, coupé and station wagon variants were introduced on the Sigma II platform (marking the first Cadillac coupe with a rear seat since the 2002 Eldorado) Applications: