What category does LevFin fall under?

Short answer is, it depends on the set-up of each bank, and who funds a LevFin trade and how profits would be split.

From an investment banking "product" (parallel to industry coverage) perspective, LevFin ranks on par with equity (e.g. ECM, structured equity/derivatives, etc), IG/FIG DCM, M&A, and/or other financing or advisory groups (if a bank is large enough to have them). So technically, LevFin should fall under the IB umbrella.

What's the rationale for some hybrid set-up (e.g. LevFin being a JV between IB and corp bank or markets) or even completely under corp bank? To a large extent, this depends on balance sheet allocation/usage for LevFin trades. In markets where LevFin primarily rely on a bank's own balance sheet (e.g. Asia Pacific), you tend to see more of a hybrid or even complete corp bank model. For example, at my bank, the ultimate lending relationship is owned by the corp bank side (as they are the ones at risk in terms of long-term hold), while we take the underwriting and syndication risk. Typical credit approval would require sign-off from both IB and corp bank. Simply put, we in the LevFin team do all the sexy work (and earn upfront fee/skim, and also be the first one to take loss if a trade blows up), and our corp bank colleagues take and hold the long-term credit exposure (and earn regular interest income/credit spread). To facilitate how deals are done, and more importantly how capital would be allocated efficiently and deal profits be split fairly inside the (big) bank, my team is structured as a JV between IB and corp bank.

We do physically sit on the IB floors though.

The other extreme would be a LevFin team without any balance sheet but doing purely advisory work. They'd certainly be housed under IB. But I doubt there are many no BS type of LevFin desks out there, as LevFin as a product has become quite commoditized, and #1 value-add to clients is your balance sheet.

Let me know if above helps. Be happy to address further questions.