KISS note refers to the Keep It Simple Security — a published template for early-stage convertible fundraising, offered in debt and equity flavors.

How it works

500 Global released KISS to give founders pre-negotiated documents instead of bespoke convertible note drafts. The debt version behaves like a convertible note with interest and maturity; the equity version converts more like a SAFE into preferred at qualifying events.

Typical fields include valuation cap, discount rate, qualified financing threshold, and optional MFN clauses. Investors sign the same form; founders fill in economics.

Why it matters

• Founders: Faster and cheaper than fully custom docs, but you still inherit conversion stack complexity when you raise a priced round. Stack KISS, SAFEs, and notes in one model before signing.
• Investors: KISS is familiar to angels who have seen 500’s ecosystem docs. Verify which version you hold and how it ranks against other convertibles.

The debt KISS accrues interest until conversion or maturity; the equity KISS skips interest but may convert on smaller triggering events. Both may include most-favored-nation clauses that auto-upgrade terms if you later issue friendlier convertibles — a stacking risk founders overlook.

Legal counsel still bills to customize schedules and side letters; KISS reduces negotiation surface area, not zero legal review.

Common mistake

Assuming “simple” means “harmless.” Multiple KISS tranches with different caps create messy cap-table cleanup at Series A.

Practical takeaway

Before closing multiple KISS or SAFE tranches, build one conversion model with all caps and discounts stacked. Legal simplicity at signing does not guarantee cap-table simplicity at Series A — cleanup costs real lawyer hours.

Related ideas

• SAFE and convertible note
• Valuation cap and discount
• Qualified financing threshold