If the DOJ estimate (which is always inflated, let's be real here) is $85M how could they have possibly made more than $123M on it? Unless you're talking about other hypothetical bribes that we don't know about.
Mixture of time value of money and interest/inflation.
You take that 85 Million and invest it (likely into growing a business unit but lets ignore that) and over 10 years it becomes greater than 85 million.
I might be splitting hairs here, but they say $85M in profit, not revenue, so presumably that would be margin on top of whatever they paid people to do nothing, and the fine is a portion of revenue that otherwise wouldn't have gone to them, of which $85M was profit.
Otherwise though, McKinsey was awarded $209M in federal gov contracts in Canada over 12 years, so the numbers themselves don't seem relatively outrageous in terms of what McKinsey makes news for.
$85M in 2014 dollars is $113M in 2024 dollars, and something tells me McKinsey didn't just leave the money sitting in a high yield savings account all this time