The pledges are understood to have been in place prior to partners of the Scottish firm voting for the tie-up with its much larger rival in December last year but details have only just emerged. Among those said to be in line for the six-figure sum are Caryn Penley and Allan Wernham, joint managing partners at the firm. Ms Penley will be the only D&W partner who will be joining the CMS board.
D&W chairman Laurence Ward is another the guarantee is said to apply to.
A two-year partner lock-in period is also thought to have been agreed as part of the merger, formally scheduled to complete in May.
Dundas & Wilson said it was not making any comment. CMS Cameron McKenna said there were inaccuracies in the report in the legal trade press but declined to specify.
A spokeswoman for the firm said it did not comment on the details of partner terms. She added that as far as CMS was concerned "the merger is really good news for clients and ambitious young Scottish lawyers that want to be part of a global legal practice".
Other D&W partners named in the article in The Lawyer were Glasgow-based construction disputes specialist Lindy Patterson and Edinburgh corporate partner Kenneth Rose, who is believed to play a key role in the firm's relationship with Royal Bank of Scotland. London corporate partner David Gibson and real estate's Alistair Kennedy were mentioned as receiving the guarantee.
It was suggested other partners will go on to CMS's tiered equity structure.
D&W, which has offices in Scotland's three largest cities as well as London, had been in the market for a merger for several years.
Around two years ago, it walked away from a deal with London-based Bircham Dyson Bell following an initial round of talks.
The firm, traditionally one of Scotland's largest and with roots going back to the 18th century, has been battling with reduced fee income and fierce competition alongside the backdrop of a poor economy.
McGrigors was one the first of the big Scottish names to disappear after it merged into Pinsent Masons in May 2012. A recent report by accountancy firm BDO said further consolidation in the Scottish legal market was inevitable.