SBICs & Warrants:
SBICs usually invest 10-25% of their funds as equity alongside their core product which is mezz debt, commonly IO and 11-12%.
Occasionally they will include warrants as part of the debt instrument, either in lieu or in addition to the equity. Warrants are like stock options (= create upside potential).
Their motivation for warrants, which will typically yield ~5% of ownership, is to increase the IRR of the debt (from 11-12%) to improve the risk-reward profile (to 13-15%). Other common ways to adjust the risk-reward profile would be to raise the rate, lower the loan amount, or expedite amortization.
IMO it is better with a clean loan and having SBICs pari passu on the equity side. If they insist on warrants, however, then make sure to communicate the dilutive effects of the warrants in your pro-forma to the other investors.
Positive perspective: warrants signal that the SBIC recognizes your equity upside, positions themselves as a partner (not just a lender), and is ready to inject add'l capital for future M&A add-on activity.