Group by user task, not org chart. Limit top-level to ~7 items.
Run a card-sort with users; collapse adjacent concepts; promote the primary task.
A shop that files a product under the team that owns it internally (“Business Unit 4”) hides it from the shopper looking for “camping gear”. Good IA groups by how people think about the task, not by the org chart, and keeps the top level short enough to scan. When Amazon or a solid docs site gets this right, you find things by guessing the correct category on the first try; when it's wrong, search becomes the only way through.
Search-first products (a huge catalogue, a sprawling knowledge base) lean on strong search and filters more than a perfect tree, because no hierarchy scales to millions of items. And expert tools sometimes mirror a domain's real structure even when it looks complex, because that structure is the mental model the expert already carries.
A 14-item top nav competes with a 12-item sidebar. Users can't find anything.