Stone Ridge Asset Management, the New York based alternative risk premia focused investment manager, has continued to grow the insurance-linked securities (ILS) assets under management of its mutual reinsurance fund strategies to just over $5.8 billion, which is now the highest level they have sat at in more than six years.Stone Ridge Asset Management has been benefiting from investor appetite for alternatives and its relatively uncorrelated reinsurance investment fund strategies have proved popular, with inflows of capital continuing to fuel their growth.Over one billion in assets under management have been added in each of the two last years now, as the mutual insurance-linked securities (ILS) fund strategies offered by Stone Ridge now stand doubled in size since as recently as April 2023.When we last covered Stone Ridge’s mutual ILS funds, they had increased to almost $5.3 billion of assets across the strategies in the quarter of record to April 31st 2025, with catastrophe bond investment fuelling most of this expansion.

That trend has not changed, as cat bonds remain the major asset type invested in with the growth capital raised in the latest quarter of record.Across the mutual ILS funds, Stone Ridge added more than 5% in assets over the latest quarter, to July 31st 2025, with the combined AUM reaching $5.56 billion.That figure is after subtracting the cross-investment that Stone Ridge’s multi-asset class alternatives fund makes into its more cat bond focused fund.

Including it, the combined reported AUM at July 31st was just over $5.61 billion.But growth has continued since July and Stone Ridge has continued to add new investor flows through the last few months as well, which takes reported AUM to at least $5.87 billion by September 26th, or around $5.82 billion after subtracting the cross-investment allocation.Recall that, Stone Ridge had previously grown assets across its two main dedicated ILS mutual funds to more than $6.9 billion in early 2019, but by the middle of that year the effect of catastrophe loss activity and investor flows reduced the total to just under $5.8 billion by July 2019.

Now, AUM is back at its highest level since that date for these mutual ILS funds, while at the same time Stone Ridge has also meaningfully grown its private reinsurance and ILS funds as well, making the asset manager a much larger player in global reinsurance markets at this time.Impressively, at over $5.8 billion of combined assets across the Stone Ridge mutual ILS funds, they have now doubled in size since as recently as April 2023 and added more than one billion dollars in AUM over the last two years.The most catastrophe bond focused of the mutual fund strategies, the Stone Ridge High Yield Reinsurance Risk Premium Fund, had total net assets of $3.53 billion at April 30th 2025, which had grown to $3.66 billion by July 31st and has increased further to $3.85 billion by last week.

This cat bond focused strategy has now grown by more than $600 million in assets in just the last year and more than doubled in size since around April 2023.The Stone Ridge Reinsurance Risk Premium Interval Fund, that invests across the spectrum of ILS and reinsurance-linked assets with a greater focus on sidecars and private quota shares, as well as other collateralized reinsurance arrangements.and to a lesser degree catastrophe bonds, had increased slightly to $1.16 billion as of April 30th 2025, but grew further to $1.23 billion by July 31st and again to almost $1.3 billion by last week’s NAV.

The portfolio disclosure as of July 31st shows new investment allocations to quota shares and private reinsurance sidecar arrangements, as this fund’s holdings continue to refresh and legacy positions and exposures are worked through.The Stone Ridge Reinsurance Risk Premium Interval Fund is now at its largest size since around April 2022, and while its growth has been slow over the last year there are definite signs of growing stability in the asset base and positions it holds.Stone Ridge’s third mutual fund strategy where it allocates to catastrophe bonds, ILS and reinsurance opportunities, is the Stone Ridge Diversified Alternatives Fund, a multi-strategy fund that began adding ILS investments to its portfolio in 2023.

The ILS and reinsurance assets held by this fund grew to almost $624 million by April 30th 2025, while its cross-investment back into Stone Ridge’s cat bond strategy was $17.8 million at that time.By July 31st 2025, the Stone Ridge Diversified Alternatives Fund held $724 million of catastrophe bonds and other private ILS or reinsurance investments, while the cross-investment had increased to around $54.56 million.Direct cat bond investments have been the main component of ILS allocation growth for this Stone Ridge Diversified Alternatives Fund, now reaching over $540 million by July 31st 2025, while the overall ILS portion of the fund has grown to now 40% of the total strategy, up from 37.5% at the end of April this year.

Stone Ridge has continued to grow these mutual ILS funds alongside the very active catastrophe bond market in recent years.But in the last quarter, which covers the mid-year 2025 renewal season, there is also more evidence of growth into reinsurance quota shares and collateralized reinsurance investments as well.They remain the largest examples of dedicated catastrophe bond and interval style mutual ILS fund strategies, while the Diversified Alternatives fund has one of the largest ILS allocations of any multi-strategy registered fund offering.

At over $10 billion, Stone Ridge remains one of the largest investment manager of ILS and reinsurance assets, in AUM terms, featured in .All of our Artemis Live insurance-linked securities (ILS), catastrophe bonds and reinsurance can be accessed online.Our can be subscribed to using the typical podcast services providers, including Apple, Google, Spotify and more.