Bridge rounds: How companies fund the gap before a big raise or an IPO

A bridge round is a smaller, interim funding round that a company raises between two big ones. Its job is to keep the company running until a larger event arrives, such as a major financing or a stock market listing.

The idea is simple, but the terms around it, such as pre-money value, caps and discounts, confuse many readers. This guide takes them one at a time.

A bridge works like a loan for the gap before payday

Imagine you are waiting for a large bonus in three months, but rent is due next week. You borrow a modest sum to cover the gap, and you repay it when the bonus lands. A bridge round does the same for a company.

AngelList’s learning guide describes a bridge round as interim financing raised between larger funding rounds to keep a startup operating until its next major raise. Accounting references describe bridge financing more broadly as a temporary fix for short-term costs until longer-term funding arrives. Sources differ on how long a bridge lasts: one says a few months to a year, another says 6 to 24 months.

Who uses bridges, and for what reasons

AngelList lists three typical users. Struggling startups use a bridge to buy time to change course. Growing startups use one to reach milestones that could support a higher valuation later. Late-stage companies use one before an initial public offering, or IPO, the first sale of shares to the public.

Its example for the last group is Robinhood, which raised a $1 billion bridge round in January 2021, about six months before its IPO.

Because a bridge can mean either distress or momentum, the label alone says little. Readers need to look at who is investing and why.

Pre-money and post-money: The two numbers in every headline

Funding stories usually quote a valuation, and the two versions differ. Pre-money valuation is the estimated worth of a company just before the new cash arrives. Post-money valuation is that worth after the cash is added.

The formulas are short. Post-money equals pre-money plus the new investment. The new investors’ ownership equals their investment divided by the post-money value. A worked example from the SuperMoney encyclopedia: a $100 million pre-money company takes $25 million, giving a $125 million post-money value and a 20% stake to the new investors.

Apply the same arithmetic to the reported OpenAI round. Our news story on the round says CNBC’s sources describe up to $30 billion at a $1.25 trillion pre-money valuation. If the full amount were raised, the post-money value would be $1.28 trillion, and the new money would buy roughly 2.3% of the company. This is our own illustration; the real figure depends on final terms that no one has confirmed.

Notes, caps and discounts decide who gets what

Bridges can take different legal forms. AngelList says convertible debt is the most common, usually a convertible note, because it is fast to close. A convertible note is a loan that later turns into shares instead of being repaid in cash.

Two terms protect the lender. A valuation cap sets a ceiling on the price at which the note converts, often tied to the previous round’s post-money value. A discount lets the bridge investor convert at a reduced price in the next round. Sources cited here give discounts in a range of 10% to 20%, though AngelList’s own example uses 40%.

Its worked case: a startup raised a $5 million Series A at a $10 million post-money valuation, then a $2 million bridge, then a $10 million Series B at $30 million post-money. With a $10 million cap, bridge investors convert as if the Series B were priced at $10 million. With a 40% discount, they effectively invest at $18 million.

A bridge can also use preferred shares, which usually follow the terms of the last priced round, especially when the same investors take part.

Why a bridge can be a sign of strength or strain

The risks differ by side. For founders, AngelList notes that a low bridge valuation can deter later investors, and that a bridge often signals distress. Investors may feel pressure to keep funding a struggling company to protect their stake. AngelList also warns that labels such as “plus” or “prime” round can disguise a bridge, and that not every bridge leads to a successful next round.

Another risk is a down round, where a company’s new pre-money valuation falls below the previous round’s post-money value. Investors in a weak company may demand that.

An IPO bridge is a different case. The company is not short of cash in the same way; the round may simply add capital ahead of a listing. In the OpenAI report, CNBC’s sources call the raise “opportunistic”, per our news story, and the story’s own reading is that a private bridge would let OpenAI raise cash without setting a listing date.

What to watch when a bridge is reported

Several details turn a headline into something readers can judge:

• Size: “up to” means the final amount may be lower.
• Form: shares or convertible debt, and whether a cap or discount applies.
• Investors: whether existing backers return and who leads.
• Timing: whether the money arrives at once or in stages, and whether an IPO date follows.
• Confirmation: whether the company itself announces the round.

Reports based on anonymous sources describe a deal in progress, not a signed one. Until the company confirms, the numbers are estimates. The same caution applies to the Robinhood-style pattern: a large bridge before a listing is common enough to be a known category, but each deal’s terms are its own.