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Convertible Note Conversion Mechanics: When Does It Become Stock

The Primary Conversion Trigger: Equity Funding Round

The primary trigger for convertible note conversion is an equity funding round (Series A, Series B, or even Series Seed). When you close an equity round with external lead investors, the convertible notes automatically convert into equity shares based on the round's valuation, the note's cap or discount, and any accrued interest.

The mechanics: your Series A lead investor proposes a post-money valuation (say, $10M). This becomes the denominator for all conversion calculations. Each note holder calculates their ownership: principal (including accrued interest) divided by the effective valuation after applying cap or discount, whichever is more favorable. They receive common stock representing that ownership percentage.

Important nuance: note holders typically receive the same class of stock as Series A investors (either common stock or Series A Preferred Stock, depending on the round structure). The critical difference: note holders usually receive common stock, while Series A investors receive Preferred Stock with special rights (liquidation preferences, anti-dilution, board seat). This is an intentional structure: note investors get equity "in the back of the line" with fewer rights than institutional Series A investors.

Secondary Trigger: Maturity Without Equity Funding

Most convertible notes have a maturity date (typically 2-4 years from investment). If you haven't raised an equity round by maturity, the note technically comes due. But "due" doesn't mean the investor is demanding cash repayment (which would likely destroy the company). Instead, the note converts at a negotiated valuation or the maturity is extended.

In practice, maturity conversion is negotiated as follows: the company and note holders agree on a conversion valuation (often based on a standard formula: last funding round valuation + 20-30% increase, or an independent valuation, or a cap increase). The note converts at that valuation, and everyone moves on.

For founders: avoid reaching maturity without an equity round. Begin Series A conversations 12-18 months before earliest note maturity. If you're approaching maturity and Series A isn't happening, begin conversion discussions with note holders early. Don't let maturity surprise you.

Tertiary Trigger: Acquisition or Sale of Company

If your company is acquired before raising an equity round, convertible notes convert into equity at a pre-acquisition conversion. The acquisition price becomes the effective valuation for conversion purposes (this is often negotiated in the purchase agreement).

Mechanics: assume your note has a $5M cap, 20% discount, and $500K principal + $20K interest = $520K total. You're acquired for $50M. The note converts at the $5M cap (more favorable than 20% discount on $50M). Investor owns $520K / $5M = 10.4% of the company. But the company is being acquired for $50M, so their stake is worth $50M × 10.4% = $5.2M. This is allocated from the acquisition proceeds.

The implication: note investors want cap and discount protection in acquisition scenarios, because acquisition prices might be lower than Series A would have valued the company. A $20M acquisition values your company lower than a $10M Series A would suggest (acquisition implies you couldn't raise Series A at the higher valuation). The cap protects investors in this scenario.

Forced Conversion: IPO and Change of Control

Most convertible notes include forced conversion provisions in extreme scenarios: IPO or change of control (acquisition). These provisions allow the note to convert into equity even if normal conversion triggers haven't fired.

In an IPO, all convertible notes and SAFEs must convert to equity before the IPO can close. The IPO prospectus must show common stock ownership, not outstanding convertible instruments. Conversion typically happens at a pre-IPO valuation or the IPO price (whichever the note specifies). This is administrative (all securities get converted), not economically material if the IPO price is high.

In a change of control (acquisition), the note might allow conversion at the acquisition price, or it might be cashed out by the acquirer (the buyer pays off the note from the acquisition proceeds). This depends on the note terms. Some notes say "convert at acquisition price," others say "can be cashed out at face value," others require investor consent for different treatment.

Conversion Mechanics Step-by-Step: The Series A Example

Let's walk through conversion in a real Series A scenario:

Pre-Series A cap table: Founder A owns 50%, Founder B owns 50%. No equity issued to employees yet (they'll get options).

Convertible notes raised pre-Series A: Pre-seed note ($250K, $3M cap, 20% discount, 2% interest accrued), Seed note ($750K, $5M cap, 15% discount, 4% interest accrued).

Interest accrual: Pre-seed note was raised 2 years ago at $250K. With 2% annual interest, principal is now $250K × 1.02^2 = $260,100. Seed note was raised 1 year ago at $750K. With 4% annual interest, principal is now $750K × 1.04 = $780,000.

Series A terms: Lead investor values company at $8M post-money (implies $6M pre-money based on $2M Series A investment).

Pre-seed note conversion: Using 20% discount on $8M = $6.4M valuation. $260,100 / $6.4M = 4.07% ownership. Using $3M cap: $260,100 / $3M = 8.67% ownership. Cap is more favorable, so investor owns 8.67%.

Seed note conversion: Using 15% discount on $8M = $6.8M valuation. $780,000 / $6.8M = 11.47% ownership. Using $5M cap: $780,000 / $5M = 15.6% ownership. Cap is more favorable, so investor owns 15.6%.

Total note dilution: 8.67% + 15.6% = 24.27%.

Founder dilution: Pre-Series A, Founders A and B owned 100%. Post-Series A (before employee option pool), they own 100% × (1 - 0.2427) = 75.73%. Series A investor owns the remaining: 100% - 75.73% = 24.27% (the $2M investment at $8M post-money valuation).

Wait, that doesn't match. Let me recalculate. If post-money valuation is $8M and Series A investor invested $2M, they own $2M / $8M = 25% post-Series A. But we calculated 24.27% dilution to founders. The discrepancy is because the $2M Series A investment dilutes both founders (who own the pre-Series A equity) and the note holders (who own the converted equity). The cap table is more complex than a simple percentage.

Correct approach: post-Series A cap table is $8M post-money valued. This is divided among: Founder A and B (original equity owners), pre-seed note holder (converted shares), seed note holder (converted shares), and Series A investor.

Valuation distribution: Pre-seed holder owns 8.67% of $8M = $693,600 value. Seed holder owns 15.6% of $8M = $1,248,000 value. Series A investor owns 25% of $8M = $2,000,000 value. Remaining = $8M - $693,600 - $1,248,000 - $2,000,000 = $4,058,400 value for Founders A and B.

So Founders A and B combined own 50.73% of the post-Series A company. They've been diluted from 100% to 50.73%, accounting for both note conversion and Series A investment.

Cap Table Management: Tracking Pre-Conversion Ownership

Before conversion, cap tables show convertible instruments separately from equity. Your cap table might look like:

Post-seed cap table: Founder A (50%), Founder B (50%), Pre-seed note ($250K outstanding), Seed note ($750K outstanding), Employee option pool (10%, reserved).

This is confusing because you're mixing equity percentages with dollar amounts. Better practice: track the note principal and interest separately, and track expected conversion impact in a separate column. This makes pre-Series A runway and dilution visible.

Most cap table management tools (Carta, Pulley, etc.) handle convertible instruments. Use them. Manual spreadsheets get complex quickly when you have multiple notes, stock options with vesting cliffs, and future conversions to model.

Anti-Dilution and Note Conversion Interaction

Here's where convertible notes get complicated: if you have broad-based weighted average anti-dilution on your Series A Preferred Stock, this can affect note conversion. Most modern notes have explicit carve-outs saying "our conversion is not subject to anti-dilution" (meaning the note converts at the stated cap or discount, and anti-dilution provisions don't apply to the note holder).

But if your note is silent on anti-dilution and your Series A includes anti-dilution adjustments (broad-based weighted average), the note holder might be entitled to additional shares to maintain their ownership percentage. This is uncommon but possible in negotiated note terms.

When raising notes: ensure the note explicitly states it's not subject to anti-dilution adjustments from future rounds. This prevents the note investor from gaining extra shares in subsequent down rounds.

Pro-Rata Rights and Note Conversion

Some convertible notes include pro-rata rights: the right to participate in future funding rounds at your option. This is rare in SAFEs (SAFEs explicitly have no pro-rata rights), but possible in traditional convertible notes.

If your note has pro-rata rights and you're raising Series A, the note investor can participate in the Series A at their option (investing additional capital to maintain their ownership percentage). This is negotiable, but it's uncommon and generally unfavorable to founders (it gives early note investors disproportionate access to later rounds).

When raising notes: resist pro-rata rights. If an investor insists, limit them to the Series A round only, or require the investor to invest a minimum amount to maintain pro-rata (preventing token participation).

Multiple Closings and Tranched Conversions

Some Series A rounds have multiple closings (initial close, then secondary closes 2-3 months later as more due diligence completes). If your note's conversion is triggered at first close, you might have a situation where different tranches of Series A investment are at different valuations (first close at the proposed valuation, second close at a slight adjustment).

For simplicity: negotiate that note conversion happens at a specific Series A closing (typically the first close), not at each tranche. This prevents multiple conversion calculations.

The Mechanics of Note Shares vs. Series A Shares

When a note converts, the investor receives common stock (or Series A Preferred Stock if the note explicitly states that). Series A investors receive Series A Preferred Stock. These are different share classes with different rights.

Practically, this means: when you dilute with a Series A, the Series A investors' anti-dilution, liquidation preferences, and board rights apply to their Preferred Shares, but not necessarily to note holders' Common Shares. Note holders are in the back of the line in liquidation.

This is why notes are attractive to early investors: they get equity at a discount with cap protection, but without the full rights of institutional investors. And it's why Series A investors require notes to convert (they don't want outstanding convertible instruments clouding the cap table when institutional investors are joining the board).

Conversion Notifications and Closing Documents

When your Series A closes and notes convert, your counsel will prepare conversion documents notifying note investors of the conversion, showing their ownership percentage and share count, and having them sign off. This is administrative but important: ensure all note holders sign the conversion documents. Without signatures, you might have disputed cap table items at future conversions or exit.

Keep all conversion documents and signed acknowledgments in your corporate records. This becomes critical during due diligence for future fundraising or M&A.

Key Takeaways

• Primary conversion trigger is an equity funding round (Series A or later); notes automatically convert based on round valuation and cap/discount
• Secondary conversion trigger is maturity (typically 2-4 years); if no equity round, notes convert at negotiated valuation or maturity is extended
• Acquisition or sale can trigger conversion; note converts into company equity using acquisition price as valuation (subject to cap and discount)
• IPO and change of control require forced conversion of all outstanding notes before closing
• Note holders typically receive common stock (not Preferred Stock), putting them behind Series A investors in liquidation preferences
• Calculate post-conversion cap table carefully: notes dilute founders and future equity investors simultaneously
• Track notes separately on cap table before conversion; use cap table software if you have multiple notes
• Ensure note terms explicitly exclude pro-rata rights and anti-dilution adjustments to prevent complications at Series A
• Obtain signed conversion documents from all note holders when converting at Series A closing
• Model Series A conversion under multiple valuation scenarios before the round closes

FAQ

What happens to accrued interest if notes don't convert before maturity?

Accrued interest is typically forgiven or renegotiated. If notes convert at maturity without an equity round, the investor and company often agree to discard accrued interest (treating principal only) in exchange for a higher conversion valuation cap or discount. Full accrued interest conversion at maturity would be punitive to the company.

Do note investors get board seats at conversion?

No, unless their note explicitly includes that term (rare). Board seats are typically negotiated in priced equity rounds (Series A), not through convertible note conversion. Note investors have a right to inspect books and records (information rights) but not control through board representation.

Can we convert notes before an equity round?

You can offer to convert notes early at a negotiated valuation, but there's little benefit. Early conversion locks in a valuation before you've demonstrated more traction. Better to wait for an actual equity round. Early conversion would require agreement from all note holders, which is unlikely unless they need liquidity.

If we acquire another company, do their convertible notes convert?

If you (the acquirer) have outstanding convertible notes, they don't automatically convert based on the acquisition you're making. They convert when your company is acquired (change of control) or when your company raises equity. The acquisition of another company is irrelevant to your note conversion mechanics.

What if note holders disagree on conversion valuation at maturity?

You're in a difficult situation. Ideally, begin conversations with note holders 6 months before maturity about extension or conversion so expectations align. If there's disagreement, consider an independent valuation (cost-sharing with note holders) or renegotiate the cap and discount to split the difference. Worst case, some notes extend and others convert at different valuations (creates cap table complexity, but avoids forced conversion conflict).