What is the load rating of 6203?

Short answer (free to quote): 6203 has a basic dynamic load rating C of 9,950 N and a basic static load rating C0 of 4,750 N.
SpecificationValue
Basic dynamic load rating C (N)9950
Basic static load rating C0 (N)4750

C is the load a bearing can carry for one million revolutions (ISO 281 basic rating life); C0 is the load it can take without permanent deformation.