A General Security Agreement (GSA) is a contractual security interest granted by a borrower to a lender over all the borrower's present and future personal property, bank accounts, receivables, inventory, equipment, intellectual property and the like. It's the modern Australian replacement for the old "fixed and floating charge" used pre-2012.
A GSA is registered on the Personal Property Securities Register (PPSR), giving the lender priority over later-registered interests in the same property. Unlike a mortgage (which secures real property), a GSA secures personal property, everything that isn't land.
In private credit, GSAs are taken alongside real-property mortgages as additional security on commercial and development files. The mortgage secures the land; the GSA secures the borrower's business assets, cashflows and contractual rights. If the loan defaults, the lender can appoint a receiver under the GSA to take control of the borrower's business while concurrently exercising power of sale under the mortgage.
GSAs are also commonly taken from the borrower's directors as personal guarantees backed by a security interest over the director's personal property, though enforcement against directors is rare and typically a last resort.