How do you add two independent master's degrees to your name?

Question

Assuming you add one master's degree (Master of Science) like that:

FirstName LastName, M.Sc.

What is a proper way to add two independent¹ master's degrees (both Master of Science)? Do you just add them both to the end?

FirstName LastName, M.Sc., M.Sc.

¹ independent: Different universities, different fields, 2x 120 ECTS = 240 ECTS in total. Not the result of a double degree program.

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Just to be clear, I am not looking for recommendations, if or when I should decorate my name with academic degrees. I do not even plan to do it on a regular basis. Even in my country, you don't do it very often. But if there is this one single time in my whole life where I should do it, then I want to do it right. That's all I am asking for: Are there rules or good/best practices on how to do it with two M.Sc. degrees.

Example situation: If you get mentioned on someone else's thesis as an examiner or as a supervisor the names will be decorated with degrees. A german doctor with three doctoral degress can either be Dr. Dr. Dr. FirstName LastName or Dr. mult. FirstName LastName. This example shows two possible rules:

1. You can stack titles/degrees. Just add as much as you have. That's from where I derived FirstName LastName, M.Sc., M.Sc..
2. You can condense - at least multiple doctoral - degrees by adding mult. to the mention of one single title/degree. I have never seen this in combination with other degrees.

Answer 1

Unless you are in a place that regulates academic titles, you can do pretty much as you please. But you could qualify each with the specific field or university if you feel the need to list both.

FirstName LastName, M.Sc.(Basket Weaving), M.Sc.(Basket Burning)

Distinguishing by university, rather than field will probably confuse people, thinking you have two masters in the same field. Qualifying with both is probably too unwieldy.

Answer 2

You don't. Even in academic circles, writing "John Smith, MS, MS" just looks silly and pompous. Instead, simply write "John Smith, MS." In the same way, you would not ask people to call you "doctor doctor" if you had two PhDs, nor would you write "MS, BS, BA" if you did a dual degree in college but subsequently got a master's.

You may want "credit" for your two different degrees, but this is not the purpose of the initials. Rather, you can list both degrees separately on your resume, or describe yourself in a bio as having "two master's degrees."

Granted, this answer is from a US perspective; it is possible that this would look less silly to members of other cultures.

Answer 3

There are some indications that one could use MMSc to designate a double 'master of science'-degre.

Here is an example of a profile who calls himself Dr. ... MMSc.

As for the rationale behind that, I may cite this Wikipedia section on representing plurals in acronyms:

In some languages, the convention of doubling the letters in the acronym is used to indicate plural words: for example, the Spanish EE.UU., for Estados Unidos ('United States'). This old convention is still followed for a limited number of English abbreviations, such as SS. for "Saints", pp. for the Latin plural of "pages", paginae, or MSS for "manuscripts".

This approach of pluralizing acronyms is quite common with academic titles in German, e.g. DDr. for "Doktor Doktor", or MMag. for "Magister Magister". Thus, MMSc would serve as an analogy.

Interestingly, https://en.wikipedia.org/wiki/MMSC does state that the acronym may refer to "Double Master of Science, an academic degree". And if you google around, you find some examples of such usages.