It depends on the type of loan...
Criminal usury is defined by PA 259 of 1968 with a cap of 25%. PA 52 of 1970 exempts loans to business entities - essentially whatever the bank & business agree to in writing is what stands.
The revised banking code (PA 276 of 1999) effectively eliminated a lot of the specific usury limits by loan type - used to be 16.5% max on auto paper, for example.
Generally you're safe with a 25% limit on consumer or mortgage credit, but if you have questions it's best to consult counsel.
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Opinions are Bartman's, not those of my employer. "A noble spirit embiggens the smallest man."