A priority claim with priority over all other priority claims.
A superpriority claim under Section 507(b) can be trumped only by a Section 364(c)(1) priority claim (a priority claim granted to a lender to induce it to make an unsecured postpetition loan to the debtor—this creature, like a priming lien, is virtually nonexistent). All superpriority claims, including “super” superpriority claims under Section 364(c)(1), are unsecured and do not prime secured claims.
Lenders almost always insist that cash collateral and DIP financing orders specify that the lender will have a superpriority claim to the extent that the “adequate protection” granted to the lender under such an order proves to be inadequate. But Section 507(b) automatically provides a superpriority claim where adequate protection fails, even if the lender’s cash collateral order or DIP financing order does not mention the lender’s entitlement to such a claim.