1) When two words are made into one word, use the apostrophe where one or more letters have been removed.
Note: Stylistically, the use of contractions is not recommended for formal writing.
The apostrophe is also used to show the omission of part of a date.
For example: The Chairman will be up for re-elction in '06. (instead of 2006)
However, do not use an apostrophe to show the exclusion of letter in an abbreviation.
- Dept. (department)
- No. (number)
2) Use the apostrophe to designate possession or ownership. Place the apostrophe
before the "s" to show possession or ownership by one person.
For example: My client's case
My client's cases (one client has more than one case)
3) To designate possession or ownership by more than one person, make the noun plural
first. Then immediately use the apostrophe.
- one client's case
- two clients' cases
- one actress’s contract
- two actresses’ contracts
- one child’s guardian
- two children’s guardians
However, when using proper nouns (formal names) ending in "s" or an "s" sound, you may exclude the "s" that would normally follow the apostrophe.
Singular possession or ownership
- Mercedes-Benz’ trademark
- Mercedes-Benz’ trademarks
Plural possession or ownership
The Joneses' assets
4) When a noun is formed by several words, possession or ownership is designated with ’s at the end of the word as in the example of plural possession or ownership above.
- my mother-in-law’s stock portfolio
- the Commander-in-Chief’s mandate
5) Use the apostrophe and "s" only after the second name if two people own or possess the same thing.
- Alejandro and Fransesca’s job contracts are valid for 5 years.
- Alejandro's and Fransesca’s job contracts will be renewed next year. (separate possession or ownership)
- But: Alejandro and Fransesca’s job contracts will be renewed next year. (joint possession or ownership of more than one contract)
6) Do not use an apostrophe with possessive pronouns - hers, his, its, ours, theirs, yours.
- This client is hers, not yours.
- The company will publish its annual report next month.
- But: It’s a clear case of negligence. (The only time an apostrophe is used for "it’s" is when it is a contraction for "it is". See Rule 1 above).