The S-Curve

Welcome to The S-Curve

Now you will be able to receive the latest announcements, product updates, and our insights on the mortgage market in real time.

The name of the blog, the S-Curve, is a reflection of our logo and the central feature of our prepayment model. S-curves are seen in nature in many phenomenon, from population growth to prepayment and default models. Our first S-curve, in the early 1990s, used the arctangent function, then piece-wise linear functions, and evolved over time to be more complex and vary by FICO, loan size and LTV. This evolution encapsulates both the timeless nature of fundamental relationships and constant innovation to describe them better over time.

We hope you find the information useful and we look forward to your feedback.

Subscribe to our publications to make sure you stay up to date
Blog - Latest
  • Now Available: AD&Co’s Quantitative Perspectives

    Alex Levin, Andrew Davidson, Eknath Belbase, Mickey Storms, Nathan Salwen

    Thoughts

    We’re excited to announce two new Quantitative Perspectives that provide in-depth insights into current market trends and advanced valuation techniques. These papers offer valuable information for mortgage market participants and those involved in credit risk transfer transactions.

    Is the New “New Normal” the Old Normal? Understanding Mortgage Rates

    Explore why mortgage rates have not followed the expected path after the Fed’s easing cycle and what factors may drive future rate movements. We offer a long-term perspective and discuss how mortgage rates differ from Treasury rates, providing improved insights and benchmarks for market participants.

    READ NOW

    Valuation of Credit Risk Transfer with Embedded Calls 

    Learn how to address the challenges of valuing embedded call options in credit risk transfer transactions. Using three different approximation methods, we explore more accurate ways to estimate the market value of these options, highlighting the advantages of each approach.

    READ NOW

    Both papers will be valuable resources for your work. A login is required for access. If you have any questions or would like to discuss the content in more detail, please contact support@ad-co.com.

  • Leveraging Data and Analytics: Highlights from the IMN MSR Forum 2024

    Joni Baker

    Events

    Andrew Davidson & Co. Inc. (AD&Co) proudly sponsored the Information Management Network (IMN)’s 10th Annual Mortgage Servicing Rights (MSR) Forum, held November 21 - 22, 2024 at the New York Marriott at Brooklyn Bridge. Our servicing expert Richard Cooperstein moderated and I spoke on the panel “Leveraging Trended Data to Enhance Your MSR Portfolio’s Mortgage Prepayment and Credit Modeling.” This panel focused on enhanced consumer data, its impact on delinquencies and prepayments (as shown in our white paper), and the process to bring the data and analytics into decision-making.

    Other panels at the event discussed a variety of topics, including the interest rate outlook, macroeconomic factors, climate factors, and their effects on prepayments, escrow, originations, delinquencies, new versus seasoned MSRs, MSR supply and demand, and rate hedging strategies and functionality. The panel discussions underscored the need for a deeper understanding and management of the interest rate and credit risks embedded in the federal mortgage servicing asset. Recapture and the importance of good customer service were recurring themes throughout the conference.

    Cautious Optimism for the MSR Market

    The overall sentiment regarding MSR assets was a cautious optimism: Despite being a complex asset class, the MSR market remains strong, and people want to buy. Many panelists took the view that due to full employment, a strong GDP, and expectations about the economy and a large and increasing deficit, interest rates in 2025 would see at most a modest decrease before rising again. However, this view was not universally shared, with some pointing to a potential economic downturn and increased defaults being hinted at by delinquency trends in auto credit being close to pre-Covid levels, and the subset of Covid forbearance mortgages that will ultimately default.

    For borrowers who already have low mortgage rates, there is limited room for modification; it is interesting to note that one servicer mentioned having some mortgages in foreclosure even with low LTV. Meanwhile, some borrowers bought homes in 2023 hoping to ultimately refinance into lower rates, but the opportunity has not arisen (and might not anytime soon). Finally, due to climate factors and inflation, insurance in some areas is becoming increasingly unaffordable or unavailable. In some regions, such as Florida, some condominium owners are facing massive assessments. One servicer noted that with the current high home prices, most consumers facing high insurance increases can sell their homes. However, there is evidence that when insurance premiums rise to the level of 30-40% of principal and interest, delinquencies also begin to rise. AD&Co’s Climate Impact Suite (currently in beta testing) distinguishes between the effect of climate change on home prices (through Climate Conditioned HPA) and the effect of high premiums on borrower behavior (through Climate Conditioned LDM), with the first effect feeding into the second; if the CLTV remains low, high premiums lead to increased turnover, but if the CLTV becomes high, delinquencies increase.

    Uncertainty and the Importance of Prepayment Forecasting

    In general, and especially with the new administration coming in, uncertainty was a key theme throughout the forum. It was suggested more than once that the economy may have some curve balls. Regardless – and as always – the ability to forecast prepayment speeds is key for valuing MSR’s. Prepayments determine the total base fee collected on a mortgage, as well as the earnings on escrow and payment float, which have become larger and increasingly important components of MSR valuation due to higher interest rates.

    For current coupon mortgages, much depends on the interest rate forecast. For low-rate mortgages, however, it's important to understand the economics of turnover (especially when no rate incentive exists) and predict which borrowers are more likely to prepay at a low rate, such as 3%. The overall low prepayment rate among this set could potentially rise due to a pent-up demand to move, especially with more firms pushing for employees to return to the office.

    Many panelists spoke about recapture, which was a prominent theme of the conference: recapture refers to the situation in which the servicer retains the borrower by servicing the new loan as well. Some servicers account for recapture in their valuation, and some use models for predicting recapture rates. The necessity of providing excellent customer service arose in multiple panels as essential for increasing recapture and selling ancillary products while also reducing delinquencies and defaults.

    "Know Your Data and Your Portfolio"

    One panelist observed that, in the current environment, it is now more important than ever for servicers to “know your data and your portfolio”. The topic was addressed during the AD&Co-moderated panel “Leveraging Trended Data to Enhance Your MSR Portfolio’s Mortgage Prepayment and Credit Modeling”. David Doyle of Sagent first discussed some of the challenges in understanding the strengths and risks of potential MSR acquisitions, while Gauhar Turmuhambetova of BlackRock outlined the challenges of using dynamic credit bureau data in the valuation of securitized products. Bindiya Jain of Experian described the granular loan-level insights available on their platform and specifically within their mortgage performance dataset. Then I shared research that illustrates how Experian’s trended data attributes may be used to improve mortgage prepayment and delinquency forecasts beyond what may be inferred from a traditional credit score. I also demonstrated through AD&Co’s MSRKinetics application how these improved forecasts would affect the base fee and cost components of MSR valuation for sample GSE and FHA loans, as well as their weighted average lifetimes and duration profiles.

    Overall, IMN’s MSR forum provided a rich opportunity to engage with participants in the MSR industry, learn about their views and needs, and explore potential synergies.

  • AD&Conversations: AD&Co Updates its Home Price Index Model

    Michelle Stepien Breier, Alex Levin, Matteo Caracciolo-King

    Podcast

    Tune in to Michelle Stepien Breier's interview with Alex Levin & Matteo Caracciolo-King as they discuss their latest Pipeline article “AD&Co Updates its Home Price Index Model.” The interview highlights key points from the article as they share recent updates to the HPI3 model. If you’re intrigued and eager to learn more, hit play or click the link to read the full article! 

    Login is required to access this Pipeline article. 

  • Revisiting the Capital Treatment of Credit Risk Transfer

    Andrew Davidson

    Thoughts

    With the increasing volumes of Synthetic Risk Transfer (SRT) and Credit Risk Transfer (CRT) along with the discussion of BASEL III, we thought it would be useful to re-issue our comment letter to FHFA on the capital treatment of Credit Risk Transfer. 

    CRT is not quite the same as either equity or debt from a capital perspective; however, capital rules often attempt to categorize them this way and then add ad hoc adjustments. Our comment letter addressed an appropriate framework for understanding the risk reduction impact of CRT transactions.
     

  • Panoramic Capital Podcast: Prepayment Modeling with Daniel Swanson

    Daniel Swanson

    Podcast

    Recently, senior credit modeler, Daniel Swanson had the pleasure of speaking with Rob Kessel from the Panoramic Capital Academy podcast titled, “Modeler’s Perspective on Prepayment Modeling.”  This podcast is part of the curriculum in Panoramic Capital Academy's capital market course, an accredited 14-week class for capital market professionals, including hedging mortgage pipelines and valuing mortgage servicing rights (MSRs).  The discussion covered topics like data gathering, how to forecast speeds in an ever-changing world, validating results and how modeling evolved to include more loan-specific variables.

    Click here to listen. 

    About Panoramic Capital Academy and Consulting

    Panoramic Capital Academy and Consulting offers an advanced mortgage capital markets training program, providing accessible and foundational education to the mortgage industry to accelerate careers, improve financial performance, and foster respect in the industry.  Panoramic also provides mortgage capital market consulting services.  

    More information can be found at www.panoramiccap.com.

Blog - Archives

The S-Curve Archives

  • Daniel Swanson, Joni Baker

    Thoughts

    Over the past summer, Andrew Davidson & Co., Inc. (AD&Co) was pleased to have Stephanie Duenas and Anika Chatterjee interning with us at our office in New York City. During this time, Stephanie and Anika performed a detailed analysis of mortgage performance data to consider the question of whether and how two credit scores, when available, could provide lift over a single score in predicting mortgage delinquencies.

  • Greg Schopman

    Events

    AD&Co in Action: Volunteer & Cultural Days 2026

    At Andrew Davidson & Co., Inc. (AD&Co), our values extend beyond the work we do for our clients. Humanity, inclusivity, dedication, citizenship, creativity, and integrity shape how we engage with one another and with our community. This August, members of the AD&Co team took the opportunity to put those values into practice during our Volunteer Day supporting Volunteers of America-Greater New York’s Operation Backpack® and our Cultural Day at Ellis Island.

  • Mickey Storms, Alex Levin

    Thoughts

    Recently, aggregators have crossed market borders by issuing residential mortgage-backed securities (RMBS) backed by owner-occupied (OO), GSE-eligible conforming loans. Additionally, conforming mortgage loans have drawn investment interest from insurance companies fronted by aggregators and evaluated by third-party firms. These developments constitute historically rare disintermediations of the nearly monopsonist purchases of conforming loans by the GSEs.

  • Rob Landauer, Abe Martin

    Podcast

    Join Rob Landauer in a conversation with Abe Martin as they discuss his recent Pipeline article, "Modeling the Balance Behavior of HELOC Borrowers." In this episode, they highlight key points from the article as he shares insights into the draw component of HELOCs and provide an update on the beta rele

  • Ashlea Bonds

    News

    We’re excited to announce a major addition to the Andrew Davidson & Co., Inc. (AD&Co) team. Industry leaders Kelli Sayres and Gene Park, known for building and scaling leading fixed-income analytics platforms, have joined AD&Co’s Business Development team.

  • Sanjeeban Chatterjee, Vivian Li, Joni Baker, Richard Cooperstein

    Thoughts

    Building on our earlier research on expanded consumer attributes, AD&Co continues to explore how credit data contributes to modeling delinquency and prepayment risk, which are key drivers of mortgage servicing rights cash flows and valuation.

  • Joann Gollette

    Events

    Andrew Davidson recently joined NFM Lending’s Greg Sher on the One On One podcast to discuss our recent white paper, “The Impact of Moving Away From the Tri-Merge Standard.”

  • Eknath Belbase, Daniel Swanson, Yvonne Chen

    Events

    AD&Co recently sponsored and attended SFVegas 2026 and Optimal Blue Summit 2026. This post shares the AD&Co team's unique perspectives and key takeaways from attending both conferences.

  • Alex Levin

    News

    AD&Co US Mortgage High Yield Indices

    The Federal Reserve Economic Data (FRED) portal, housed by the Federal Reserve Bank of St. Louis, has been publishing AD&Co’s CRT indices since 2019. These series posted under the overall name of “US Mortgage High-Yield” include total return rates and credit and option-adjusted spreads (crOAS) – a projected return’s spread over Treasury (in the past, Libor). These series are available going back to 2014-end and tiered by CRT initial supports.

  • Joni Baker, Sanjeeban Chatterjee, Richard Cooperstein, Andrew Davidson

    Thoughts

    In July 2025, the US Federal Housing Finance Agency (FHFA) announced that the government-sponsored entities (the Enterprises or GSEs), Fannie Mae and Freddie Mac, would permit lenders to choose between Classic FICO and VantageScore 4.0 credit score models for loans sold to the GSEs. FHFA also stated in a social media post that the tri-merge standard would be maintained for mortgage underwriting. Nevertheless, some mortgage industry stakeholders recommend moving away from the tri-merge standard for GSE mortgages in favor of a single or bi-merge report standard.