CEO - pronouncing

[Abstract Idea]

How does one pronounce CEO (Chief Executive Officer)?
Are the letters pronounced separated or is it pronounced like a whole word?

Are there any rules to similar cases pronounciation ?

[tigerpaws]

It is pronounced as separate letters. C E O not see-oh.

[Abstract Idea]

Are there any rules to similar cases pronunciation ?

.

[anupumh]

CEO is an abbriviation, thus you will say each letter of it C E O.

Abbrivaition rule of syllable stress would apply here, where you stress on the last letter of the abbriviation.

ex. CEO, IBM, MBA, etc

[Abstract Idea]

CEO is an abbriviation, thus you will say each letter of it C E O.

Ok, but I feel there are other abbreviations which are not pronounced this way.
For example:
NASA, NATO
These ones are not pronounced letter by letter, right ?

Is there any rule about that?

[anupumh]

The rule I mentioned is for Abbriviations/Initialism, where individual letter is pronounced seperately, thus effectively has more than one syllable.

The ones which you ve stated now, AIDS, NATO, UNESCO, RADAR, LASER etc are Acronyms (a word formed from the initial letters or groups of letters of words in a set phrase or series of words). An acronym is when the capital letters are pronounced as a word and not individual words.

Acronym and initialism - Wikipedia, the free encyclopedia
initialism vs. abbreviation vs. acronym

I cant think of any stress rule for them, because all of them are monosyllabic (one syllable).