400
merchants.invalid_personmerchantsRule R4The person's details are not valid
A person's national id is stored encrypted, with a blind index over its normalised form and only the last four digits in clear. This code is the validation half: ownership_percent must be between 0 and 100.
Why the API refuses
WHEN a person is added or updated, THE SYSTEM SHALL store the national id encrypted with a blind index over its normalised form, keep only its last four digits in clear, and reject an ownership_percent outside 0 to 100.
What to do
Send ownership_percent as a number in 0–100 — a percentage, not a fraction, so a 25 % owner is 25 and not 0.25.