I'm not a finance bro, just pointing out where it comes from.

https://corporatefinanceinstitute.com/resources/fixed-income/mm-millions/

In finance and accounting, MM (or lowercase “mm”) commonly denotes that the units of figures presented are in millions. The Roman numeral M denotes thousands. In this context, MM is the same as writing “M multiplied by M,” which is equal to “1,000 times 1,000,” which equals 1,000,000 (one million).

While Roman numerals are technically additive (MM is really 1,000 plus 1,000 or 2,000), MM is still a fairly common way of abbreviating millions, especially in certain industries like oil and gas. This guide will explore how the notation should be used, as well as alternative symbols that are used in practice.