Personal Loan and Promissory Note Red Flags: What to Check Before You Sign

The core terms, read these first

Before anything else, make sure the basic economics are stated clearly and match what you agreed to: the principal (the amount borrowed), the interest rate, the repayment schedule, and the maturity date when the full balance is due.

Look for the APR, not just a monthly or "factor" rate, so you can see the true annual cost. A rate quoted in a way that hides the real number, "just 2% a month," "a small fee", is worth converting to an APR before you agree. If the note is silent on any core term, that ambiguity is itself a risk.

Is there a legal limit on loan interest rates?

Interest can be simple (charged only on the principal) or compounding (charged on principal plus accrued interest), and the difference over time is large. Confirm which applies, and how often it compounds.

Most states set a maximum legal interest rate (a usury cap) for certain loans. A rate above that limit can be unlawful and, in some cases, unenforceable, a signal that the loan is predatory. If a rate seems very high, it is worth checking your state's usury rules before signing rather than after.

What do state usury laws and federal tax rules say about personal loans?

Usury caps are set state by state, and they mostly bite on private lenders such as individuals and small businesses, because banks, credit unions and licensed finance lenders are usually exempt. In California, Article XV, section 1 of the state constitution limits interest on a loan made primarily for personal, family or household purposes to 10 percent a year when the lender is not an exempt institution. Florida Statutes § 687.03 sets the general maximum at 18 percent per year simple interest for loans of $500,000 or less.

New York has two tiers. General Obligations Law § 5-501 and Banking Law § 14-a set a civil cap of 16 percent a year, and Penal Law § 190.40 makes interest above 25 percent criminal usury. In Adar Bays, LLC v. GeneSYS ID, Inc. (2021), New York's highest court confirmed that a loan found usurious is void, meaning neither the principal nor the interest can be collected, and held that the same applies to a loan to a corporation that exceeds the 25 percent criminal cap. Short-term notes are annualized, so a four-month loan at 12 percent works out to 36 percent a year.

Family loans raise a federal tax question rather than a usury one. Internal Revenue Code § 7872 treats a below-market loan as if the lender charged interest at the applicable federal rate, which the IRS publishes monthly, and then gave the forgone interest to the borrower as a gift. For gift loans directly between individuals, the rule does not apply on any day the total outstanding balance between them is $10,000 or less, unless the money is used to buy income-producing assets. Larger family loans with little or no interest are where professional tax advice earns its fee.

Before you sign, convert any stated rate to an annual figure, check it against your state's cap for that type of lender and loan, and keep a signed copy of the note with your payment records.

What happens if I miss a payment on a promissory note?

The acceleration clause is one of the most important in any note. It says that if you default, often even by a single missed payment, the entire remaining balance becomes due immediately, not just the payment you missed. A small stumble can turn into a demand for the whole loan at once.

Read exactly what counts as a default, and whether you get notice and a chance to cure (fix a missed payment) before acceleration kicks in. A note with a hair-trigger default and no cure period leaves very little room for an ordinary life event.

Prepayment penalties, late fees, and default interest

Check whether you can pay the loan off early without a penalty. Some notes charge a prepayment penalty precisely to protect the lender's expected interest, which punishes you for being responsible. A borrower-friendly note lets you prepay freely.

Then read the fee structure: late fees, and especially a higher "default interest rate" that kicks in after a missed payment. A default rate several points above the normal rate can make catching up much harder, turning a temporary problem into a spiral. Know these numbers before you need them.

Collateral, security, and personal guarantees

Is the loan secured or unsecured? A secured note is backed by collateral, a car, property, or other asset the lender can take if you default. Make sure you know exactly what you are pledging, because a secured note can cost you the asset, not just your credit.

For business or larger loans, watch for a personal guarantee, where you agree to be personally responsible even if the borrower is a company. That pierces the protection a business entity normally provides and puts your personal assets on the line. It is a significant commitment that deserves its own careful read.

Cosigning is borrowing

If you are being asked to cosign, understand that you are not just vouching for someone, you are legally on the hook for the full debt if they do not pay. The lender can often come after you first, and the loan will typically appear on your credit and count against your own borrowing capacity.

People cosign for family and friends out of goodwill, then discover a default has become their problem. Before cosigning, ask whether you could actually afford to repay the entire loan yourself, because that is exactly the risk you are taking on.

What is a balloon payment on a loan?

Check whether the scheduled payments actually pay the loan off by the maturity date, or whether a large lump sum, a balloon payment, comes due at the end. A note structured with low monthly payments and a big balloon can look affordable month to month while setting up a payment at the end you may not be able to cover.

Ask for an amortization schedule, or at least confirm in plain terms: if I make every scheduled payment, is the balance zero at the end? If the answer is no, you need to know the size of the final payment and have a realistic plan for it. A balloon is not automatically bad, but it is a very different loan from one that fully amortizes, and it should never be a surprise.

Loans between friends and family

The friendliest loans cause some of the worst fallout, precisely because nothing gets written down. A casual "pay me back when you can" has no rate, no schedule, and no shared understanding, which is exactly how a loan quietly becomes a resentment. Putting even an informal loan into a simple written note protects the relationship as much as the money.

A short note stating the amount, the interest rate (even if it is zero), and a repayment schedule keeps everyone honest and gives both sides the same expectations. For larger sums there can also be a tax dimension, very large loans made with little or no interest can raise imputed-interest questions, so if the amount is significant, it is worth a quick word with a tax professional. This is general information, not tax advice, but the theme holds: write it down, even among people you trust.

A worked example

A small business owner borrows $20,000 from a relative using an online template with a 10% late fee, acceleration on any missed payment and no grace period. A single late payment could make the whole balance due immediately. Adding a 10-day grace period and written notice before acceleration protects the borrower without harming the lender.

Put family loans in writing

A written note with a clear rate, schedule and signatures protects both sides and helps with tax treatment of interest.

Keep payment records

Pay by traceable methods and keep records of every payment. If the lender later claims you missed payments, your records are your proof, and they help settle the balance if the loan is paid off early.

Red flags to catch before you sign

A loan document deserves a slow read, however trusted the source. Run it past this list before you sign.

• A rate quoted to hide the true APR, or a rate above your state's usury cap.
• An acceleration clause with no notice or chance to cure a missed payment.
• A prepayment penalty that charges you for paying the loan off early.
• A steep default interest rate that makes catching up much harder.
• Collateral or a personal guarantee you did not fully register you were giving.
• Being asked to cosign a loan you could not afford to repay yourself.
• Vague or missing core terms, principal, rate, schedule, or maturity date.