What’s the possessive of a name ending in “s”?
Most style guides recommend adding the apostrophe and “s” like normal: James’s. But some argue that it should depend on which version feels most natural to pronounce, so that you could instead write James’, without the additional “s.”
We recommend the first approach, adding the “s” consistently, as it’s recommended by most authorities. Whatever you choose, be consistent about how you form the possessive of a particular name. Don’t write James’ at some points and James’s at others.