I'm looking at the financial definition of series: a group of stocks or options that have common characteristics. Source

How would I form the possessive and plural of this term? I'm guessing it is series' and series respectively.

Sample sentences, not sure of correctness:

He purchased one series.

 

He purchased multiple series.

 

This one series' characteristics are worth researching. <- This feels like it should be series's, but it looks so wrong.

 

These series' value is unmatched.

I'm looking at the financial definition of series: a group of stocks or options that have common characteristics. Source

How would I form the possessive and plural of this term? I'm guessing it is series' and series respectively.

Sample sentences, not sure of correctness:

He purchased one series.

He purchased multiple series.

This one series' characteristics are worth researching. <- This feels like it should be series's, but it looks so wrong.

These series' value is unmatched.

I'm looking at the financial definition of series: A group of stocks or options that have common characteristics. Source

How would I form the possessive and plural of this term? I'm guessing it is series' and series respectively.

Sample sentences, not sure of correctness:

"He purchased one series."

"He purchased multiple series."

"This one series' characteristics are worth researching." <- This feels like it should be series's, but it looks so wrong.

"These series' value is unmatched."

I'm looking at the financial definition of series: a group of stocks or options that have common characteristics. Source

How would I form the possessive and plural of this term? I'm guessing it is series' and series respectively.

Sample sentences, not sure of correctness:

He purchased one series.

He purchased multiple series.

This one series' characteristics are worth researching. <- This feels like it should be series's, but it looks so wrong.

These series' value is unmatched.