Auto-collateralisation is a credit operation that is or can be triggered, when a buyer does not have sufficient funds to settle a securities transaction, in order to improve its cash position for the next settlement cycle. The credit provided can be secured using securities already held by the buyer (âÂÂcollateral stocksâÂÂ) or the securities that are being purchased (âÂÂcollateral flowsâÂÂ).