A bridge round is a type of financing that provides a startup with interim capital between major funding rounds. It "bridges" the gap between a company's current financial position and its next significant milestone — whether that is a Series A, Series B, or a liquidity event like an IPO.
Why Do Startups Raise Bridge Rounds?
Startups raise bridge rounds for several strategic reasons:
- Extended timeline to milestones — The company needs more time to hit the metrics required for a strong next round
- Market conditions — A difficult fundraising environment may make it harder to close a full priced round
- Opportunity capture — A time-sensitive opportunity (acquisition, major contract, product launch) requires immediate capital
- Valuation optimization — The company wants to delay pricing a round until it achieves a higher valuation
How Bridge Rounds Are Structured
Bridge rounds typically use one of these instruments:
- Convertible notes — Debt that converts into equity at the next priced round, usually with a discount (10-25%) and a valuation cap
- SAFEs (Simple Agreement for Future Equity) — Similar to convertible notes but without interest rates or maturity dates
- Priced rounds at flat valuation — Sometimes bridges are structured as small priced equity rounds at the last round's valuation
Bridge Round Sizes
Bridge rounds are typically smaller than full venture rounds:
- Pre-seed to Seed bridge: $500K to $2M
- Seed to Series A bridge: $1M to $5M
- Series A to B bridge: $3M to $15M
- Late-stage bridge: $10M to $100M+
In the AI sector, bridge rounds can be significantly larger due to the capital-intensive nature of model training and GPU procurement.
Bridge Rounds vs. Extension Rounds
These terms are sometimes used interchangeably, but there is a distinction:
- Bridge round: New capital from potentially new investors, bridging to a future round
- Extension round: Additional capital from existing investors added to the most recent round, often at the same terms
Risks and Signals
Bridge rounds can be a yellow flag for investors. They may signal:
- The company is struggling to raise a full round
- Key metrics are not meeting expectations
- The market has cooled on the company's sector
However, bridge rounds are increasingly common and normal in the AI space, where companies may need interim capital to scale infrastructure before demonstrating revenue milestones. Many successful AI companies have used bridge financing strategically.
Real-World Examples
In the AI ecosystem, bridge rounds have become particularly common for infrastructure-heavy startups that need GPU compute before they can demonstrate product-market fit. Companies building foundation models often raise bridges to fund training runs that will unlock their next major valuation milestone.