There are different kinds of "business logic". Consider partitioning it based on how it's related to other layers or services. Here are some rules of thumb from an MVC perspective:
a) In the database (stored procedure) if it's mostly data-related, and can be done with joins and relatively simple WHERE and SELECT clauses.
b) In the controller if it's mostly routing or dispatching related; that is, larger-scale UI flow control in terms of screen or resource selection.
c) In the model or view-model if it involves complex or intricate computations and/or conditionals.
d) In the view (such as Razor) if it's primarily a display issue, such as "friendly" re-formatting and relatively simple to implement. (If it's complex, consider putting it in a view-model.)
