Bamboo Insurance Services
Homeowners Insurance
the Majors Fled.
It Picks What Burns Less.
On August 28, 2026, Bamboo Insurance Services filed an S-1 with the SEC. It writes homeowners insurance in California, a market hit by the Los Angeles wildfires of January 2025 and one the majors had been pulling back from well before that. One number recurs through the prospectus, in the summary and in the body alike: over the last five fiscal years its loss ratio ran an average of 32 percentage points better than the industry.
The chart the filing offers as evidence, opened year by year, is below. In four of the five years the gap stays under 20 points. Only 2025 opens to 110. Take the simple average of the five and you get 32; take the average of the four without 2025 and you get 12.
What happened in 2025 is plain enough. The loss ratio of the ten largest California homeowners insurers jumped to 175%; Bamboo came in at 65%. It was the wildfire year. Bamboo’s houses burned too. Far fewer of them did.
Why not more? The company gives two reasons: risk selection and aggregation management. As the measure of the first, the filing says roughly 98% of its California policies sit in wildfire risk categorized as moderate or lower. The founder sets the five-year loss ratio and that 98% side by side in his letter and writes: that is not luck, that is disciplined underwriting.
Ten questions. We lay out only what the S-1 says.
- Q1What is this company, really?
- Q2What is it competing on?
- Q3How big is the market?
- Q4Who uses it?
- Q5How does it make money?
- Q6Are the numbers healthy?
- Q7Who runs it?
- Q8Who controls it?
- Q9What does it fear?
- Q10What happens to the money raised?
- —Closing: beyond the ten questions
Q1 and Q2 are free. Q3 onward is a one-time $25 unlock. Unlock the full piece for $25 →
Question 1
What is this company, really?
Primary source · from the S-1
Prospectus Summary (p.1 onward), Business (p.113 onward) — from the S-1
In one line: a company that sells insurance and bears almost none of the claims.
What Bamboo handles is homeowners insurance. It quotes, it decides what to accept, it collects the premium. When something happens it adjusts the claim. To the policyholder it looks like an insurance company.
The difference is that the name on the policy is not Bamboo. A partner carrier issues the insurance, and that carrier and the reinsurers behind it are the ones who ultimately bear the loss. Bamboo’s revenue is mostly commission.
Not entirely, though. The prospectus says the company does not assume “significant” balance sheet insurance risk — not that it assumes none. It keeps a small vehicle of its own that does take risk. Question 5 opens that.
The prospectus calls this business an MGU, a managing general underwriter. It runs the design, the underwriting and the claims handling, and leaves most of the risk on someone else’s balance sheet.
The scale: managed premium of $766 million in 2025, up 58% from $484 million the year before. For the twelve months to June 2026 it reaches $879 million.
The headcount running that was 290 at the end of June 2026. The office is in Midvale, Utah, and the company owns no real property. Most roles, it says, can be performed remotely.
A company that underwrites California houses does not have its head office in California. That is what a business that keeps risk off its own books looks like.
It walked in the year everyone else was walking out
The legal beginning was November 2017, a limited liability company formed in Arizona. It began writing in 2018, and the premium it managed at the end of that year was about $2 million.
The founder’s letter does not treat that timing as an accident. It says the company launched in California in 2018, at a moment when most carriers were exiting the market, and that the timing was deliberate.
Seven years later its share of that state is 4%. $766 million is more than 380 times $2 million.
Not a company that underwrites insurance. A company that sells a way of underwriting it.
Question 2
What is it competing on?
Primary source · from the S-1
Business (Our Competitive Moats, p.114 onward), Business (Our Data-Driven Underwriting, p.122 onward) — from the S-1
It competes in three places: a number, the providers of capital, and selection.
The prospectus lists six strengths: underwriting excellence, diversified capacity providers, broad distribution, operating expense efficiency, a high-retention customer base, and an experienced management team. Read them in order and it becomes clear that all of them hang off the first.
Good underwriting attracts capital. Capital means the agent does not get turned away. Not turning agents away means more policies, more data, and better underwriting again. The prospectus calls this a flywheel. What starts the wheel is a single number: the loss ratio.
The one number everything starts from
The sentence the company keeps repeating is this one.
The components: a gross loss ratio including catastrophe losses averaging 55% over five years, against 86% for the ten largest California homeowners insurers on a weighted average basis. The chart it rests on is titled “California Loss Ratio Outperformance.” The spread is tighter too — a standard deviation of 11% against 45%.
A loss ratio is the share of collected premium that goes back out in payments. Those payments include not only the claims themselves but the cost of investigating and settling them. Lower is better underwriting. The gap here is more than 30 points. Note that 55% against 86% shows as 31 on the page, while the company writes 32. Where the 32 comes from is opened in Question 6.
This number carries the whole of the company’s case. The capacity providers arriving, the agents coming over — all of it starts here. Which is why Question 6 opens this number and no other.
Keep reading
- Q3 How big is the market?
- Q4 Who actually uses it?
- Q5 How does it make money?
- Q6 Are the numbers healthy?
- Q7 Who runs it?
- Q8 Who controls it?
- Q9 What is it afraid of?
- Q10 What becomes of the money it raises?
- Closing Beyond the ten questions