What is a negative pledge clause and how does it affect future secured lending?

A negative pledge clause is a promise a corporation makes in a loan agreement not to grant a security interest over its assets, or over specified assets, to any other lender without the existing lender's consent. Unlike an actual security interest, it isn't registered under the Personal Property Security Act and doesn't itself give the existing lender rights against the corporation's collateral — it's purely a contractual restriction on what the corporation can agree to do in the future.

Because it's contractual rather than a registered proprietary interest, a negative pledge clause generally doesn't defeat a later lender's PPSA-perfected security interest if the corporation breaches the clause and grants security anyway — the new lender who properly registers can still generally obtain an effective, perfected interest, even though the corporation broke its promise to the first lender. What the negative pledge clause does give the first lender is a contractual breach it can act on, typically triggering a default under its own loan agreement, with whatever remedies that default provides for. It's a behavioural constraint on the borrower, not a substitute for taking actual registered security.