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Bridge Financing: When Convertible Notes Are Your Best Option

What Is Bridge Financing?

Bridge financing is capital raised specifically to "bridge" the gap between one funding round and the next. It's typically done with convertible notes, though some use SAFEs or simple debt agreements. The goal: raise enough capital to extend runway until Series A closes.

Bridge rounds usually happen 6-12 months before Series A, when your seed capital is running low but Series A fundraising is underway. Instead of raising more expensive priced equity or cutting costs, you raise a bridge to buy time.

When Bridge Financing Makes Sense

Scenario 1: You have Series A investor interest but they need time. VCs move slowly. Your bridge buys 6 months while due diligence happens.

Scenario 2: You're hitting milestones that will justify a higher Series A valuation. Rather than raising priced equity now at a low valuation, you bridge to next quarter's milestone, then raise Series A at a better price.

Scenario 3: Your seed investors want to follow-on but can't until you hit a metric. A bridge lets you add capital from new investors while existing investors decide on follow-on.

Scenario 4: Series A timeline extended unexpectedly, but you have strong momentum. Bridge keeps the lights on without disrupting your Series A plan.

When Bridge Financing Doesn't Make Sense

Don't do a bridge if Series A is uncertain. If you're still early in conversations with Series A investors, a bridge buys a few months but doesn't solve fundamental problems. You'll just be in a worse position in 6 months (less runway, more dilution).

Don't do a bridge if you're cutting costs anyway. If you're down to 6 months runway and Series A is uncertain, neither a bridge nor cost-cutting fully solves the problem. You need either clearer Series A path or a pivot.

Don't do a bridge if your existing investors won't follow-on. If your seed investors won't bridge, that's a signal they've lost confidence. That's a problem you should address, not hide with external financing.

Bridge Mechanics: How They Differ from Standard Convertible Notes

Bridge notes are usually simpler than standard convertible notes. Standard notes have caps, discounts, interest rates, all negotiable. Bridges often use standardized terms:

Typical bridge structure: $100K-$2M from a mix of existing and new investors. Convertible note with a high cap (often uncapped or at a 3x-4x multiplier of Series A valuation), low/no discount, 0% interest, and a maturity date tied to Series A closing.

Why simplified? Because bridge investors expect to hold the note briefly. They convert at Series A within 6-12 months, so they don't need aggressive terms. They're betting on your Series A happening soon.

Valuation Cap in a Bridge Round

Bridge caps are often higher than seed caps because conversion is closer. If you're 6 months from Series A at $8M valuation, a bridge cap of $6M-$7M doesn't give investors much discount (their Series A shares might have been worth ~$8M anyway).

Some bridges use "post-money cap" where the cap automatically becomes the pre-money valuation for Series A. This ties bridge terms to Series A performance and prevents disputes.

Other bridges are uncapped—no maximum valuation. This is founder-friendly because bridge investors convert at whatever Series A prices, period. It's rare but happens when you have serious Series A offers in hand and investors believe in the outcome.

Existing Investor Follow-On in a Bridge

Seed investors often participate in bridge rounds. This is healthy—it shows continued confidence. But it complicates negotiations because you're dealing with existing relationships, not just new investors.

Existing investors know your situation intimately. They might push for favorable terms (low cap, high discount) in exchange for follow-on capital. This is negotiation leverage you have to navigate carefully. You want them to stay invested in your success, not resentful of their bridge terms.

Raising a Bridge from New Investors

New bridge investors are betting on your Series A executing soon. They're not evaluating your company from first principles like seed investors do. They're evaluating your Series A risk: how likely is this to close, and at what valuation?

Pitch to new bridge investors accordingly. Show Series A progress: investor meetings completed, due diligence stage reached, expected close timeline. Provide term sheets if you have them. This builds confidence in the bridge outcome.

New bridge investors often come from your existing investor network or secondary networks. They're betting on your lead Series A investor more than on your company per se.

Bridge Terms: Negotiation Playbook

Cap: Argue for cap equal to Series A pre-money valuation plus a small buffer (e.g., "Cap is Series A pre-money or $8M, whichever is lower"). This limits their discount.

Discount: Bridges rarely have discounts. If investors want one, push for 0-10% max. Higher discounts don't make sense for 6-month holding periods.

Interest: Push for 0% interest. The appreciation from Series A growth is their return. Interest is unnecessary.

Maturity: Tie maturity to Series A close, not a fixed date. This removes repayment risk if Series A delays.

Anti-dilution: Some bridge notes include broad-based weighted average anti-dilution (protection against down rounds). This is investor-aggressive. Resist or propose narrow-based instead.

Bridge Amount: How Much Should You Raise?

Calculate conservatively. If Series A is expected in 6 months and your monthly burn is $50K, a $300K bridge buys you 6 months plus a buffer. Add 20-30% buffer for Series A delays. So raise $350K-$400K.

Don't raise more than necessary. Larger bridge rounds mean more dilution and longer repayment obligations if Series A doesn't happen. Smaller bridges are founder-friendly.

Also consider: does this bridge get you to positive metrics? If you're 4 months away from PMF signals or customer milestones, a bridge that extends exactly to that point is ideal.

Bridge as a Negotiating Tool with Series A

A bridge can actually help Series A negotiations. When a VC sees you've raised a bridge with other quality investors, it signals confidence in near-term Series A. It also proves you can execute fundraising (always a good signal).

Conversely, a large bridge can spook Series A investors—it signals you're burning capital faster than expected or delaying your raise for strategic reasons.

What Happens If Series A Doesn't Close

This is the bridge risk. If your Series A falls through, you have a maturity date approaching and bridge note holders expecting conversion. You have three options:

Option 1: Extend the bridge note with investors' agreement. Most bridge investors will extend if you show continued traction and Series A progress.

Option 2: Convert the bridge into equity at a formula-based valuation (based on recent metrics or investor consensus). This is messier but avoids maturity crisis.

Option 3: Raise Series B instead. If Series A stalled but momentum is strong, you might jump to Series B. Unusual but possible.

Plan for these contingencies before signing a bridge. Ask investors about flexibility.

Bridge + Series A Discount Interaction

If bridge holders also participate in Series A, their bridge conversion and Series A participation create complex cap table dynamics. Model this carefully. Do they convert bridge then buy Series A shares separately? Or does bridge convert at Series A discount? Ask for clarity in the bridge note terms.

Key Takeaways

• Bridge financing extends runway between seed and Series A using convertible notes or SAFEs
• Only do bridge if Series A path is clear (investor interest, timeline known)
• Bridge terms are typically simpler than seed terms: high caps, low/no discounts, 0% interest
• Negotiate bridge caps and discounts based on Series A expectations, not seed stage valuations
• Plan for Series A delays and have contingency plans if Series A doesn't close

Frequently Asked Questions

Q: Can I do multiple bridge rounds?
A: Technically yes, but it looks bad. Multiple bridges signal Series A difficulty. Stick to one bridge.

Q: Should I tell Series A investors about my bridge round?
A: Yes, mention it in fundraising materials. Transparency is better than surprise cap table complications.

Q: Can existing seed investors lead my bridge?
A: Yes, and it's common. They have information advantage and can make fast decisions.

Q: What's the typical bridge size?
A: $300K-$1M, sometimes more. Depends on your burn rate and Series A timeline.

Q: Is a bridge more dilutive than priced equity?
A: Depends on terms, but generally bridges are less dilutive because they convert at higher valuations than priced seed rounds.