A group of company insiders has reportedly told industry paper Automotive News that the return and exposure from the flagship model wouldn't be enough justify the expense in producing it.
If such a model had been put into production, it would have been an extravagant, low-volume, luxury sedan with a price well above US $100,000.
However, Cadillac has not abandoned its plans to build a large, rear-wheel-drive rival to the BMW 7 Series and the Mercedes-Benz S Class on the Omega platform, with the car due to be complete in 2016 or 2017.
According to one of the company insiders, the rumoured flagship model - which also would have been built on the Omega platform - was not different enough to the car already being developed.
But while GM has frozen plans to build a flagship Cadillac for now, concepts like the 2003 V16-powered Cadillac Sixteen and the 2011 Ciel convertible have fuelled persistent rumours that the carmaker will eventually build something more exclusive.
The Ciel in particular is believed to preview several features on the upcoming BMW 7 Series and Mercedes-Benz S Class rival.