A promissory note and a security agreement are two separate documents that together create a secured loan. The promissory note is the borrower’s written promise to repay a specific amount of money on specific terms. The security agreement pledges particular property as collateral so the lender can seize and sell that property if the borrower doesn’t pay. Neither document does the other’s job. A lender who signs only a note has a personal claim against the borrower but no collateral; a lender who signs only a security agreement has a lien with no underlying debt to enforce.
What the Promissory Note Does
The promissory note creates the debt. It states how much was borrowed, the interest rate, and exactly when and how the borrower must pay. Repayment might be equal monthly installments, a single lump sum at maturity, or on demand whenever the lender asks. The note also fixes a maturity date, which is the final deadline for paying off any remaining balance.
Just as important, the note makes the borrower personally liable. The lender can sue the borrower individually for what’s owed and pursue a general judgment against them. Standing alone, though, the note gives the lender no claim to any specific property. If the borrower defaults and has no reachable assets, the note by itself may be worth little in practice. That gap is what the security agreement fills.
What the Security Agreement Does
A security agreement is a separate contract tying specific property to the debt. The borrower pledges particular assets as collateral: equipment, inventory, vehicles, accounts receivable. If the borrower stops paying, the lender can go after that property directly instead of relying on a general judgment.
The agreement has to describe the collateral clearly enough that someone reading it could identify what’s covered, and it has to contain language actually granting the lender a security interest in that property. Without the grant-of-interest language, the document is just a list of assets with no legal effect.
One boundary worth flagging: security agreements under UCC Article 9 cover personal property such as equipment, inventory, and receivables. They do not cover real estate. When land or buildings serve as collateral, lenders use mortgages or deeds of trust, which run under a different legal framework entirely.
How the Two Documents Work Together
A security interest doesn’t spring into existence just because paper was signed. It takes effect through a process called attachment, which requires three things at once:
- The lender gives value, which usually means advancing the loan funds.
- The borrower has rights in the collateral. You can’t pledge property you don’t own or have a right to possess.
- The borrower signs a security agreement describing the collateral. An oral agreement won’t do; the UCC requires an authenticated written agreement unless the lender takes physical possession of the collateral instead.
Once those three conditions are met, the security interest attaches and is enforceable between the borrower and the lender. The promissory note supplies the first element in most transactions, because it documents the value the lender gave and the debt being secured. That’s why the two documents are usually signed together: the note establishes what’s owed and the borrower’s personal liability, and the security agreement ties that specific debt to specific property.
Why Perfection Matters
Attachment makes the security interest enforceable against the borrower. It doesn’t protect the lender from anyone else. For that, the lender needs to perfect the interest.
The standard way to perfect is filing a UCC-1 financing statement with the appropriate state office, usually the Secretary of State. The UCC-1 must include the debtor’s name, the secured party’s name, and a description of the collateral.1Legal Information Institute. Uniform Commercial Code 9-502 – Contents of Financing Statement, Record of Mortgage as Financing Statement The filing puts other lenders on public notice that the collateral is spoken for. A lender can also perfect by taking physical possession of tangible collateral, or, for certain intangibles like deposit accounts, by obtaining control.
Perfection controls priority. When the same collateral is pledged to more than one lender, the general rule is that the first to file or perfect wins.2Legal Information Institute. Uniform Commercial Code 9-322 – Priorities Among Conflicting Security Interests in and Agricultural Liens on Same Collateral An unperfected lender sits behind virtually everyone, including a bankruptcy trustee who can avoid the lien entirely. That is why lenders file the UCC-1 immediately after closing.
The filing also has a shelf life. A UCC-1 stays effective for five years, then lapses automatically unless the lender files a continuation statement within the six months before expiration. If the filing lapses, the security interest becomes unperfected and the lender loses priority, even though the underlying loan may still have years left to run and the security agreement is still fully in force. Missing that renewal is a common way lenders quietly lose the protection they thought they had.
Reaching Collateral Acquired Later
A security agreement can also cover property the borrower doesn’t own yet. An after-acquired property clause extends the lender’s interest to collateral the borrower picks up later, such as new equipment, restocked inventory, or receivables generated after closing. The security interest attaches to those future assets the moment the borrower acquires rights in them.3Legal Information Institute. Uniform Commercial Code 9-204 – After-Acquired Property, Future Advances
There are limits. An after-acquired property clause generally cannot reach consumer goods unless the borrower acquires them within 10 days after the lender gives value, and it cannot attach to commercial tort claims at all.3Legal Information Institute. Uniform Commercial Code 9-204 – After-Acquired Property, Future Advances For business borrowers with revolving collateral pools like inventory and receivables, though, these clauses are standard. Without one, the lender’s collateral would shrink every time the borrower sold a product or collected a payment.
What Happens on Default
Default is where the two documents visibly do different jobs. The promissory note defines what counts as a default: missed payments, most obviously, but often also things like letting insurance on the collateral lapse or breaching financial covenants.
Acceleration
Most notes include an acceleration clause. On default, the lender can declare the entire remaining balance immediately due instead of waiting for each installment to come due one at a time. Without acceleration, a lender would have to sue separately over each missed payment, which is impractical for a multi-year loan.
Repossession and Sale
After default, the lender has the right to take possession of the collateral. This can happen through a court order, but the UCC also permits self-help repossession without going to court, as long as the lender doesn’t breach the peace.4Legal Information Institute. Uniform Commercial Code 9-601 – Rights After Default, Judicial Enforcement, Consignor or Buyer of Accounts, Chattel Paper, Payment Intangibles, or Promissory Notes The statute doesn’t define “breach of the peace” precisely, but it generally rules out physical force, breaking into a locked building, or repossessing over the borrower’s on-the-spot objection.
Before selling, the lender must send the borrower reasonable notice of the planned sale.5Legal Information Institute. Uniform Commercial Code 9-611 – Notification Before Disposition of Collateral The sale itself must be commercially reasonable in every respect: method, timing, place, and terms all have to reflect what a reasonable lender would do to get fair value. A fire-sale price or an insider discount invites a challenge.
The borrower keeps a right to redeem the collateral until the lender completes the sale or signs a binding contract to sell. Redemption means paying the full amount owed, not just the missed payments, plus the lender’s reasonable expenses and attorney fees.6Legal Information Institute. Uniform Commercial Code 9-623 – Right to Redeem Collateral Once the collateral is sold, that window closes for good.
How Sale Proceeds Are Applied, and Where the Note Comes Back In
Sale proceeds don’t go straight into the lender’s pocket. The UCC sets a specific order: first, the reasonable costs of repossession and sale, including attorney fees if the agreement provides for them; second, the debt owed to the lender that conducted the sale; third, any subordinate lienholders who made authenticated demands.7Legal Information Institute. Uniform Commercial Code 9-615 – Application of Proceeds of Disposition, Liability for Deficiency and Right to Surplus Any surplus goes back to the borrower.
More often, the sale doesn’t cover the full debt. The borrower remains personally liable for the deficiency, and that is where the promissory note does its work: the note is the document that established personal liability in the first place, so the lender can sue the borrower for whatever balance the collateral didn’t cover.7Legal Information Institute. Uniform Commercial Code 9-615 – Application of Proceeds of Disposition, Liability for Deficiency and Right to Surplus The security agreement got the lender to the collateral. The note gets the lender to everything else.
How Long the Note Stays Enforceable
The right to sue on a promissory note isn’t open-ended. Under UCC Article 3, the lender must bring an action within six years of the due date stated in the note. If the lender accelerates the balance after a default, the six-year clock runs from the accelerated due date.8Legal Information Institute. Uniform Commercial Code 3-118 – Statute of Limitations
Demand notes work a little differently. If the lender makes a demand, they have six years from the demand to sue. If no demand is ever made and no payment of principal or interest has been received for a continuous 10-year stretch, the right to enforce the note expires entirely.8Legal Information Institute. Uniform Commercial Code 3-118 – Statute of Limitations Individual states have adopted variations, so the specific deadline in any given case depends on applicable state law.