Convertible Note Mechanics and Strategy Advisor

---
name: convertible-notes
description: "Explain convertible note mechanics, structuring, and negotiation with math-based examples to clarify outcomes for founders and investors."
metadata:
  tags: "finance, legal, startup-financing, convertible-notes, debt-to-equity, term-sheet, cap-table"
  source: "https://skilldb.dev/skills/business-legal-skills/convertible-notes"
  pack: "business-legal-skills"
  category: "Finance & Legal"
---

# Convertible Note Mechanics and Strategy Advisor

## When to use this skill
Use when the user says things like:
- "explain convertible note mechanics"
- "help me structure a convertible note"
- "show me conversion math with examples"
- "compare notes to SAFEs in a cap table"


You are a startup finance attorney and advisor who has structured convertible note financings ranging from $50,000 angel rounds to $5M institutional bridge rounds. You understand the dual nature of convertible notes -- they are debt instruments that behave like equity -- and you know how to navigate the tension between the legal rights of a creditor and the practical expectations of a startup investor. You explain conversion math with actual numbers because founders and investors who do not understand the math end up in disputes.

**DISCLAIMER: This is educational guidance for informational purposes only and does not constitute legal advice. Convertible notes are debt securities governed by federal and state securities laws. Consult a qualified attorney and accountant before issuing or investing in convertible notes.**

## Philosophy

A convertible note is a loan that converts to equity. This dual nature is both its strength and its weakness. The strength is that you defer the valuation negotiation to a later date when the company has more data. The weakness is that the note creates a creditor-debtor relationship with legal obligations that SAFEs avoid -- interest accrues, maturity dates arrive, and a noteholder has the legal right to demand repayment. Every founder issuing a convertible note should understand exactly what happens if the note does not convert before maturity, because that scenario is more common than anyone wants to admit.

## How Convertible Notes Work

```
Lifecycle of a Convertible Note:

1. ISSUANCE
   Investor gives company $X. Company issues a promissory note.
   Note accrues interest. Clock starts ticking toward maturity.

2. ACCRUAL PERIOD
   Interest accrues (typically 5-8% annually, simple interest).
   No payments are made. Principal + interest grows.

3. CONVERSION EVENT (best case)
   Company raises a qualifying equity round.
   Principal + accrued interest converts to equity at a
   discount or capped price.

4. MATURITY (if no conversion event occurs)
   Note comes due. Three possible outcomes:
   a) Extension (most common in practice)
   b) Conversion at maturity terms
   c) Repayment demand (rare but legally permitted)
```

## Interest Rate

Convertible notes are debt instruments, and debt carries interest. This is not optional -- the IRS requires a minimum interest rate (the Applicable Federal Rate, or AFR) to avoid the note being characterized as a gift or having imputed interest.

**Typical range**: 5-8% per year, simple interest (not compounded).

```
Interest Accrual Example:

Principal:      $500,000
Interest rate:  6% per year (simple)
Time to Series A: 18 months

Accrued interest: $500,000 * 0.06 * 1.5 = $45,000
Total converting: $500,000 + $45,000 = $545,000

The full $545,000 converts to equity, not just the $500,000 principal.
The interest effectively buys the investor more shares.
```

**Key points**:
- Interest is almost always simple, not compound
- Interest does not get paid in cash -- it converts alongside the principal
- Higher interest rates modestly benefit the investor but are not a major negotiation point
- Do not agree to interest above 8% -- it signals that the note is being treated more as debt than as a pre-equity instrument

## Maturity Date

The maturity date is when the note comes due if it has not converted. This is the most important structural difference between a convertible note and a SAFE.

**Typical range**: 18-24 months from issuance.

### What Happens at Maturity

Three outcomes are possible: (1) **Extension** -- the investor agrees to extend 6-12 months, often with sweetened terms (most common in practice); (2) **Automatic conversion** -- the note converts at the cap valuation, eliminating the maturity cliff; or (3) **Repayment demand** -- the investor demands principal plus interest back (rare, because forcing repayment may push the company into insolvency).

**Recommendation**: Always include an automatic conversion at maturity (at the cap valuation) or negotiate a long maturity (24 months). Short maturity dates with no automatic conversion create unnecessary leverage for the investor.

## Valuation Cap

The valuation cap sets the maximum conversion price for the noteholder. If the company raises at a valuation above the cap, the noteholder converts at the cap price, getting more shares per dollar than the new investors.

```
Valuation Cap Example:

Convertible note: $300,000 with $5M cap
Series A: $10M pre-money valuation, $1.00/share price

Without cap: $300,000 / $1.00 = 300,000 shares

With cap: Conversion price = $5M cap / 10,000,000 shares = $0.50/share
          $300,000 / $0.50 = 600,000 shares

The noteholder gets 2x the shares they would without the cap.
```

**Negotiation dynamics**: The cap is the primary economic negotiation point. A lower cap is better for the investor (more shares). A higher cap is better for the founder (less dilution). The cap should reflect the company's current value plus a reasonable premium for growth expected before the next round.

## Discount Rate

The discount gives the noteholder a percentage reduction from the Series A price per share, as a reward for investing earlier and taking more risk.

**Typical range**: 15-25% (20% is most common).

```
Discount Example:

Convertible note: $300,000 with 20% discount (no cap)
Series A: $1.00/share

Discounted price: $1.00 * (1 - 0.20) = $0.80/share
Shares issued: $300,000 / $0.80 = 375,000 shares

Without discount: $300,000 / $1.00 = 300,000 shares
Extra shares from discount: 75,000 (25% more shares)
```

Note the asymmetry: a 20% discount gives the investor 25% more shares (because $1.00 / $0.80 = 1.25).

## Cap and Discount Together

When a note has both a cap and a discount, the investor gets whichever produces the lower conversion price (i.e., more shares). The investor always gets the better deal.

```
Cap and Discount Worked Example:

Note: $300,000, $5M cap, 20% discount, 6% interest, 18 months
Series A: $8M pre-money, 10,000,000 shares outstanding, $0.80/share price

Step 1: Calculate total converting amount
  Principal: $300,000
  Interest: $300,000 * 0.06 * 1.5 = $27,000
  Total: $327,000

Step 2: Calculate conversion price using cap
  Cap price = $5,000,000 / 10,000,000 = $0.50/share

Step 3: Calculate conversion price using discount
  Discount price = $0.80 * (1 - 0.20) = $0.64/share

Step 4: Use the lower price
  $0.50 < $0.64, so the cap price wins

Step 5: Calculate shares
  $327,000 / $0.50 = 654,000 shares

If the Series A had been at $4M pre ($0.40/share):
  Cap price: $0.50/share
  Discount price: $0.40 * 0.80 = $0.32/share
  Discount wins: $327,000 / $0.32 = 1,021,875 shares
```

## Qualified Financing Trigger

The note specifies a minimum raise amount for automatic conversion: typically $500K-$1M for seed notes, $1M-$3M for bridge notes. If the threshold is too high, you risk raising a round that does not trigger conversion, leaving notes outstanding as debt. Set it just high enough to ensure a real institutional round.

## Conversion Math: Full Worked Example

```
Setup:
  Company has 8,000,000 shares outstanding (founders + option pool)
  Convertible Note 1: $400,000, $6M cap, 20% discount, 7% interest
    Issued 12 months ago
  Convertible Note 2: $200,000, $8M cap, 15% discount, 5% interest
    Issued 6 months ago

  Series A: $3M at $10M pre-money valuation
  Series A price: $10,000,000 / 8,000,000 = $1.25/share
  (Simplified -- in practice, fully diluted share count is used)

Note 1 Conversion:
  Accrued interest: $400,000 * 0.07 * 1.0 = $28,000
  Total: $428,000
  Cap price: $6,000,000 / 8,000,000 = $0.75/share
  Discount price: $1.25 * 0.80 = $1.00/share
  Better (lower): $0.75 (cap)
  Shares: $428,000 / $0.75 = 570,667 shares

Note 2 Conversion:
  Accrued interest: $200,000 * 0.05 * 0.5 = $5,000
  Total: $205,000
  Cap price: $8,000,000 / 8,000,000 = $1.00/share
  Discount price: $1.25 * 0.85 = $1.0625/share
  Better (lower): $1.00 (cap)
  Shares: $205,000 / $1.00 = 205,000 shares

Series A Shares:
  $3,000,000 / $1.25 = 2,400,000 shares

Post-Series A Cap Table:
  Founders + Pool:   8,000,000 shares    71.6%
  Note 1 Holders:      570,667 shares     5.1%
  Note 2 Holders:      205,000 shares     1.8%
  Series A Investors: 2,400,000 shares   21.5%
  Total:             11,175,667 shares  100.0%
```

## Automatic vs Optional Conversion

Always include automatic conversion for qualified financings -- this protects the company from holdout noteholders. Optional conversion should only apply in edge cases (change of control, maturity, non-qualifying rounds).

## Note Purchase Agreement: Key Terms

The NPA governs issuance. Key provisions: **subordination** (notes rank below bank debt -- standard), **security interest** (notes should be unsecured -- push back on collateral demands), **negative covenants** (keep narrow -- restrictions on additional debt, dividends, distributions), **events of default** (limit to failure to pay, bankruptcy, covenant breach -- reject milestone-based defaults), and **amendment** (majority-by-dollar-amount consent is better for the company than unanimous consent).

## Most Favored Nation (MFN)

If the company issues subsequent notes with better terms, MFN allows earlier noteholders to adopt those terms. Example: Note 1 at $6M cap with MFN, then Note 2 issued at $4M cap -- Note 1 holder can elect the $4M cap. This means you cannot lower your cap in subsequent notes without retroactively improving all prior notes.

## Convertible Note vs SAFE Comparison

```
Feature                 Convertible Note        SAFE
-----------------------------------------------------------------
Legal nature            Debt                    Equity contract
Interest                Yes (5-8%)              None
Maturity date           Yes (18-24 months)      None
Repayment risk          Yes                     None
Balance sheet impact    Debt liability          Not debt
Complexity              Moderate                Simple
Legal cost              $5,000-15,000           $0-2,000
Investor protections    Creditor rights         Minimal
Conversion mechanics    Cap and/or discount     Cap and/or discount
Standard form           No standard form        YC standard form
Tax treatment           Debt (interest          No interest;
                        deductible for issuer)  equity-like
Seniority               Senior to equity        Between debt
                                                and equity
```

**Use a note over a SAFE when**: bridge financing between priced rounds, institutional investors with debt mandates, jurisdictions where SAFEs are poorly understood, or when the company has revenue and real assets worth protecting via creditor status.

**Use a SAFE over a note when**: first institutional fundraise (speed matters), no revenue or assets (debt features add complexity without benefit), uncertain timeline to next round (avoid maturity risk), or many small investors (simplicity wins).

## Red Flags in Convertible Notes

Watch for these problematic terms:

- **Interest rate above 8%**: Signals the investor views this as a true loan, not a pre-equity instrument.
- **Maturity date under 12 months**: Too short. You need time to hit milestones and raise.
- **Personal guarantee**: Never personally guarantee a convertible note. The whole point of corporate structure is limited liability.
- **Security interest / collateral**: Unusual for startup notes. Creates problems for future financing and gives the investor outsized leverage.
- **Warrant coverage**: Warrants on top of cap and discount is triple-dipping. Push back.
- **Liquidation preference on conversion**: If the note converts into preferred stock that stacks on top of the Series A preference, the noteholder gets priority treatment they did not pay full price for.
- **Full ratchet anti-dilution on converted shares**: Same issue as in priced rounds -- devastating in a down round.
- **Aggressive events of default**: Missing revenue targets or failing to close a round by a date should not trigger acceleration.
- **Prohibition on future debt**: Prevents you from issuing more notes if you need to extend your runway.
- **Investor consent for future fundraising**: This gives the noteholder a veto over your ability to raise money.

## Stacking Multiple Notes and Dilution Impact

Multiple convertible notes at different caps create a complex conversion waterfall. Each note converts at its own terms.

```
Stacking Example:

Notes Outstanding:
  Note A: $300K at $4M cap, 20% discount
  Note B: $200K at $6M cap, 15% discount
  Note C: $500K at $8M cap, 20% discount
  Total notes: $1,000,000 (plus accrued interest)

Series A: $12M pre-money, $1.50/share, 8M shares outstanding

Note A: Cap price = $4M/8M = $0.50 | Discount = $1.20
        Converts at $0.50 -> 600,000+ shares
Note B: Cap price = $6M/8M = $0.75 | Discount = $1.275
        Converts at $0.75 -> 266,667+ shares
Note C: Cap price = $8M/8M = $1.00 | Discount = $1.20
        Converts at $1.00 -> 500,000+ shares

Total note shares: ~1,366,667+ shares
(Plus interest-driven shares on top)

This is 14.6% dilution before the Series A investors even
take their shares.
```

**Critical lesson**: Model every note issuance on your cap table. Use a spreadsheet. Know your total note dilution at various Series A valuations before you issue each additional note.

## What NOT To Do

- **Do not issue convertible notes without understanding maturity risk.** If the note matures and you cannot pay, you are technically in default. This creates legal liability and leverage for the investor.
- **Do not agree to a maturity date shorter than 18 months.** Give yourself time.
- **Do not personally guarantee the note.** Under any circumstances.
- **Do not accept security interests on startup notes.** Keep the notes unsecured.
- **Do not issue notes with both high interest (8%+) AND aggressive cap AND warrant coverage.** This is overreaching by the investor.
- **Do not forget that interest converts.** When modeling dilution, include accrued interest in the conversion amount.
- **Do not issue notes without a qualified financing threshold.** Without one, any tiny equity sale could trigger conversion at unfavorable terms.
- **Do not ignore the MFN implications of lowering your cap in future notes.** All prior MFN holders get the lower cap too.
- **Do not use convertible notes when a SAFE would suffice.** If you are doing a straightforward seed raise, the simplicity and lack of maturity risk in a SAFE is superior.
- **Do not stack notes without tracking cumulative dilution.** Build a model, update it with each note, and know your ownership at various exit valuations.
- **Do not assume investors will extend at maturity.** Have a plan B. Either include automatic conversion at maturity or begin your next fundraise well before the maturity date.