Bamboo has attracted $400m of third-party funds to its Greenshoots Re reinsurance sidecar

Data-driven insurance distribution platform Bamboo Insurance Services has so far attracted $400 million of third-party funds to support its Greenshoots Re Ltd. collateralized reinsurance sidecar vehicle, recent IPO filings show.

Greenshoots Re has been called the first MGA-sponsored sidecar structure and for Bamboo it’s become an increasingly important source of capacity, bringing more reinsurance support

The importance of the reinsurance sidecar structure gets explained by Bamboo in its recent S-1 filing, as it looks to raise capital through an initial public offering (IPO).

The filings drive-home the importance and also scale of the capacity support that third-party investors are providing to Bamboo and some of the program business it underwrites, with the total funding now having reached $400 million, according to the filing.

Recall that, Bamboo first launched the Greenshoots Re reinsurance sidecar in April 2025, when it was still part of White Mountains Insurance Group and the company’s reinsurance renewal included a first reinsurance sidecar transaction via Greenshoots Re Ltd., which issued $70 million in preference shares to a broad group of institutional investors. That first deal supported business Bamboo underwrote via fronting carrier Sutton National.

The, in October 2025, the Greenshoots Re sidecar was leveraged to provide reinsurance to cover an E&S program jointly launched by Bamboo with specialty insurer Accredited, however no size was given for that transaction.

Most recently, in July 2026, Bamboo finalised a multi-year sidecar transaction through Greenshoots Re, with that deal supporting Bamboo’s new California admitted programme with MS Transverse.

With the closing of that latest sidecar transaction in July this year, Bamboo said that Greenshoots Re provided fully collateralized reinsurance to four fronting carriers within itss portfolio and that the total sidecar facility had subsequently expanded to roughly $175 million.

But, Bamboo’s S-1 filing suggests the total capital raised to support the quota share reinsurance arrangements entered into by the Greenshoots Re sidecar vehicle is actually $400 million, which drives home the scale and importance of this third-party reinsurance capital support.

In its S-1 filing, Bamboo calls the Greenshoots Re sidecar “proprietary capacity.”

The importance of that statement should not be understated, as program business and MGA players are increasingly looking to take greater control of their reinsurance needs, with the support of capital market investors and insurance-linked securities (ILS) structures of this kind.

The proprietary reinsurance capital sources provide “incremental capacity” Bamboo’s filing notes, also citing the $100 million Greengrove Re Ltd. (Series 2025-1) catastrophe bond that was sponsored by Sutton National, but provides reinsurance to support subject business that Bamboo produces for that fronting carrier (like the first sidecar deal had).

Bamboo’s S-1 filings states, “These structures reflect strong demand from alternative capital providers and enhance the breadth and flexibility of our capacity ecosystem.”

The S-1 also drives home the importance of these investor relationships, as Bamboo notes that its business could be harmed if investors were not attracted to the sidecar or cat bond and that it needs to continue to remain an attractive partners to investors seeking to access returns from reinsurance arrangements supporting its underwriting business.

It’s clear Bamboo values the investor relationships it has cultivated through the reinsurance sidecar and catastrophe bond, recognising their importance for its future business prospects and growth.

Diversifying reinsurance capacity providers to include the capital markets is key for MGA’s and program businesses in insurance these days and the $400 million size of the sidecar funding, alongside the $100 million raised for the cat bond, shows just how meaningful this capital markets support can be.

Find details of numerous reinsurance sidecar investments and transactions in our directory of collateralized reinsurance sidecars transactions.