Maxy is a Y-spelling variant of Maxi or Maxie — affectionate diminutives of Max — and at 28 records this is almost certainly a registry artifact. The standard Max ranks among the top five pet names in the US; Maxy is what happens when owners write the nickname they actually use and the licensing system records it verbatim.
Max's Long Diminutive Tail
Max generates a large family of nickname variants in registries: Maxie, Maxi, Maxy, Maxey. These variants collectively represent owners who use affectionate forms in daily life but whose formal registration differs from the common spelling. The Max-family is so dominant in pet naming that even its obscure variant spellings accumulate dozens of records each.
The Y-Suffix Affection Pattern
Adding -y or -ie to names is a universal English affection marker: Max becomes Maxy, Bob becomes Bobby, Sam becomes Sammy. These suffixed forms feel warmer and more diminutive in daily use. Gender-neutral skew here suggests Maxy sometimes gets applied as a softened female form of the typically male Max. The human name Max and its root Maximus are squarely masculine Latin.
The Counter-Reading: Spelling Inconsistency
If you want to call your dog Maxy, register them as Max and call them Maxy at home. The inconsistency between official name and call name creates no practical problem — but registering "Maxy" creates the same lifetime spelling-correction friction as any variant. Browse pet names.