Convertible notes are debt when they’re issued and become equity when they convert into stock. The instrument spends the first part of its life as a loan on the company’s balance sheet, then reclassifies as an ownership stake once a triggering event (usually a priced financing round) hits. That two-stage life is what makes the debt-or-equity question harder than it sounds: the honest answer is “both, but not at the same time,” and the accounting rules, the tax code, and the investor’s legal rights each track that shift in their own way.
The Debt Phase: What the Note Actually Is at Issuance
At issuance, a convertible note is a loan documented through a promissory note. The company records a liability equal to the principal amount, and interest accrues on that balance. Seed-stage rates have trended toward the lower end, with figures around 4% common, though the number depends on negotiation and perceived risk. Interest is sometimes simple and sometimes compounding, and it typically converts into additional shares alongside the principal rather than being paid out in cash.
Until conversion, the investor holds the legal status of a creditor, not a shareholder. In a liquidation, creditors get paid before equity holders. Most startup convertible notes are unsecured, though, so there’s no specific claim against company property if things go sideways. The creditor priority is real but limited in practice, because early-stage companies rarely have meaningful assets to distribute.
Every convertible note carries a maturity date, usually one to two years from issuance. If nothing has converted by then, the note comes due. What happens next is more nuanced than a demand for cash: most agreements let the holder choose between repayment and converting the outstanding balance into equity, usually into the most senior class of stock the company has outstanding at that point. Startups that haven’t raised a qualifying round by maturity often negotiate an extension rather than force either outcome.
Default and Remedies
If the company misses a payment or breaches a note term, the holder typically has two choices: accelerate the note (declare the full balance immediately due) or convert the balance into equity. Acceleration sounds aggressive, but suing a cash-strapped startup rarely produces a good outcome, so most investors prefer conversion. The real leverage is the conversion right, not the threat of a lawsuit.
The Conversion Event: When Debt Becomes Equity
Conversion is the whole point of a convertible note. The investor put in cash today; the payoff arrives as ownership tomorrow. Several events can trigger the shift.
The most common trigger is a qualified financing round, typically defined as the company raising at least $1 million in new equity (often a Series A). When that happens, the outstanding note balance automatically converts into the same class of shares the new investors receive. The conversion is usually mandatory once the threshold is met, so neither side has to opt in.
If the company is acquired before a qualifying round, the note holder usually receives a cash payout of principal plus accrued interest rather than converting into equity. Some agreements build in a payout multiple to compensate for the missed equity upside, but a straight return of principal plus interest is more typical in standard-form notes.
Once conversion happens, the classification question flips. What was a liability on the balance sheet becomes equity, and what was a creditor becomes a shareholder with all the rights (and lack of repayment priority) that entails.
GAAP Classification: Debt on the Balance Sheet
For financial reporting purposes, convertible notes sit primarily under ASC 470-20, the accounting standard covering debt with conversion and other options. A convertible note is generally recorded as a liability on the issuing company’s balance sheet. The principal appears as debt, accrued interest gets added over time, and the treatment continues until conversion, at which point the liability is reclassified as equity.
The accounting gets more complicated when a note includes features like variable conversion prices tied to future valuation caps. ASC 815-15 requires companies to evaluate whether these features are embedded derivatives that must be separated from the host debt contract and measured at fair value.1Financial Accounting Standards Board. Accounting Standards Update 2016-06 – Derivatives and Hedging (Topic 815) The test turns on whether the economic characteristics of the conversion feature are “clearly and closely related” to the debt instrument itself. When they’re not, the company tracks and reports the derivative component separately, which adds cost and complexity. For most seed-stage startups working with basic convertible notes, this bifurcation isn’t required, but notes with unusual terms can trigger it.
Tax Classification: The IRS Has Its Own Test
The IRS doesn’t simply follow the accounting treatment. Section 385 of the Internal Revenue Code authorizes the Treasury to issue regulations determining whether a corporate interest should be treated as debt or equity for tax purposes.2Office of the Law Revision Counsel. 26 USC 385 – Treatment of Certain Interests in Corporations as Stock or Indebtedness The statute lists five factors the regulations may consider:
- Whether there’s an unconditional written promise to pay a fixed amount with a fixed interest rate
- Whether the instrument is subordinated to or has preference over other company obligations
- How the company’s total debt compares to its equity
- Whether the instrument can convert into company stock
- Whether the holders’ interests mirror their existing stock holdings
That last factor matters because when existing shareholders hold notes in proportion to their stock ownership, the arrangement starts looking less like genuine lending and more like a disguised equity contribution.
The classification stakes are direct. If the note qualifies as debt, the company can deduct interest payments as a business expense under Section 163.3Office of the Law Revision Counsel. 26 USC 163 – Interest If the IRS reclassifies the note as equity, those “interest” payments become non-deductible dividends, and the company may owe back taxes plus penalties. Most standard convertible notes issued to outside investors in arm’s-length transactions are treated as debt before conversion. Notes between related parties or notes with terms that look more like equity contributions can face reclassification risk.
What the Investor Reports and When
Investors holding convertible notes need to track three separate tax events: interest accrual, conversion, and eventual sale of the stock.
While the note is outstanding, accrued interest is generally taxable income as it accrues, regardless of whether the interest is actually paid in cash. For straight convertible notes, the IRS treats the interest as accruing at the stated rate, assuming the note will not convert. An investor holding a note with a 5% rate reports that interest as income each year even if the company hasn’t made a payment.
When the note converts into stock, the conversion itself is generally not a taxable event. The investor doesn’t recognize gain even if the stock received is worth more than the principal amount of the loan. Any stock received in payment of accrued interest that hasn’t already been included in income will be taxable at conversion. The investor’s tax basis in the new stock equals their basis in the note (typically the principal amount) plus any interest previously reported as income.
The QSBS Holding Period Trap
Investors who hold their converted stock long enough may qualify for the Section 1202 exclusion on capital gains from qualified small business stock. For stock held more than five years, up to 100% of the gain can be excluded from federal income tax.4Office of the Law Revision Counsel. 26 USC 1202 – Partial Exclusion for Gain From Certain Small Business Stock The critical question is when the five-year clock starts. Because a convertible note is debt, not stock, the holding period for QSBS purposes generally begins when the note converts into stock, not when the note was originally purchased. An investor who held a note for two years before conversion still faces a full five-year holding period from the conversion date. If the converted stock qualifies under Section 1202(f) as stock received in exchange for other QSBS, the holding period from the prior instrument may tack on, but this argument is fact-specific and far from guaranteed with debt instruments.
SAFEs Are Not Debt at All
One boundary is worth flagging, because it’s easy to assume SAFEs and convertible notes work the same way. A SAFE (Simple Agreement for Future Equity) is the most common alternative to a convertible note in early-stage fundraising, but it isn’t debt. A SAFE carries no interest rate, has no maturity date, and creates no repayment obligation.5Y Combinator. Understanding SAFEs and Priced Equity Rounds The investor gives the company money now in exchange for a contractual right to receive shares at a future priced round.
Because a SAFE is not debt, the company doesn’t record a liability the same way, and there’s no maturity date looming as a deadline. For founders, that eliminates the risk of a note coming due before the company is ready for a priced round. For investors, it removes the creditor protections that come with debt status, including repayment priority in a liquidation. The SAFE holder is essentially betting entirely on the equity upside with no debt fallback. So if the instrument you’re actually dealing with is a SAFE, most of the debt-phase analysis above doesn’t apply.