Abbreviations made up of the first letter of each word in a phrase, usually in all capitals, do not generally use periods, with some exceptions here and there. (D.C. has periods even though it is pronounced letter by letter.) ... Some acronym abbreviations have actually become words themselves.

Should an acronym have periods?

In American English, we always put a period after an abbreviation; it doesn't matter whether the abbreviation is the first two letters of the word (as in Dr. for Drive) or the first and last letter (as in Dr. for Doctor).

How do you punctuate acronyms?

When an abbreviation comes at the end of a sentence, use only one period. However, place question marks or exclamation marks after the period in the abbreviation.