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.
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2026 Cultural and Volunteer DayEventsAD&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.
Operation Backpack®
For AD&Co’s Volunteer Day, employees participated in Operation Backpack®, Volunteers of America-Greater New York’s annual community service initiative supporting children living in New York City shelters. Operation Backpack provides unhoused K-12 students with new backpacks and school supplies, helping ensure they can begin the school year equipped with everything they need to be successful.
For the third year in a row, our team spent the morning filling backpacks with school supplies that would ultimately make their way into the hands of these local students.

We invite you to click the link for more information on Volunteers of America-Greater New York’s Operation Backpack®.
Ellis Island
For our Cultural Day, AD&Co employees took the ferry over to Ellis Island to participate in the Save Ellis Island’s Hard Hat Tour, an in-depth, off-the-path guided tour of Ellis Island’s Hospital Complex and grounds, visiting areas that were closed to the public for more than 60 years. The complex included a hospital that once cared for immigrants who arrived at Ellis Island with illnesses or medical conditions. Approximately 1.2 million immigrants were treated there over the course of its history.
Also, throughout the complex, we had the chance to see Unframed—Ellis Island, an installation by French artist JR. The site-specific works bring immigrant stories to life through historic photographs incorporated directly into the abandoned spaces. Save Ellis Island works in partnership with the National Park Service to preserve and restore these historic buildings so that this chapter of American history remains accessible to future generations.
Walking around the island gave our team a unique perspective on the history of immigration in New York City and the country as a whole and highlighted the human experiences that form an important part of American history. In the same vein, AD&Co’s culture is defined by a series of ethical and personal values that define who we are and how we operate. By recognizing our multi-cultural workforce, it allows us to operate with a wider expanse of ideas and viewpoints in our day-to-day work. Ellis Island provided a meaningful setting for reflection.

For more information on the Save Ellis Island organization or their Hard Hat Tour, please visit their website.
Values
Both of these fantastic experiences reinforce AD&Co’s commitment to fostering a culture in which different perspectives are valued, people are treated with respect, and our responsibilities extend beyond the walls of our offices.
We are grateful to Save Ellis Island and Volunteers of America-Greater New York for giving our team the opportunity to take a step back from our day-to-day responsibilities to give back to and educate ourselves about our community.
We look forward to continuing to find ways to learn, participate, and give back together.
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Now Available: AD&Co’s Quantitative PerspectivesThoughtsRecently, 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.
We're thrilled to announce our latest Quantitative Perspectives where Mickey Storms and Alex Levin present examples of how Andrew Davidson & Co., Inc. (AD&Co) financial engineering techologies can be used by loan sellers and originators to fully evaluate the economics of GSE-conforming loan pricing, GSE credit fees, and loan sale options. Click below to read the full paper.
This paper will be a valuable resource 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.
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AD&Conversations: Trends in the Home Equity SectorPodcastJoin 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 release of our much-anticipated industry HELOC model.
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Industry Leaders in Fixed-Income Analytics, Kelli Sayres and Gene Park, join Andrew Davidson & Co., Inc.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. With decades of experience, deep client partnerships, and a shared commitment to rigorous quantitative analytics, their arrival marks an exciting new chapter for our firm and the clients we serve.
Read the full press release to learn more about their backgrounds, recent work at Numerix, formerly known as PolyPaths and what this means for AD&Co.
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White Paper: Evaluating GSE Servicing Rights With Extended Consumer Credit Data: Valuation and Sensitivity AnalysisThoughtsBuilding 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.
Our latest analysis shows that while modern credit scores capture important borrower behavior, there is still meaningful explanatory power beyond any single score. Across 2,000+ consumer attributes, additional variables provide incremental insight into loan performance and mortgage servicing rights valuation dynamics.
Read Now
The S-Curve Archives
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Thoughts
As interest rates rise and fewer loans with refinancing incentive remain, other factors are primed to play a larger role in determining prepayment speeds in the coming months (and perhaps years). Turnover, the rate at which people move, is the most cited of these factors. In this blog post, we’ll consider two other potential drivers: curtailments, or partial prepayments, and mortgage payoffs that don’t involve taking out a new loan.
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Thoughts
Summary
In 2021, Andrew Davidson & Co. Inc. (AD&Co) proposed a benchmark cohort approach to setting Ability-to-Repay (ATR) Qualified Mortgages (QM) standards. Successful benchmarks based on data are model-free and transparent, and the cohorts must perform consistently in comparison to one another and across time. Our original work used data through the early stages of the pandemic when non-performing loan percentages skyrocketed.
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ThoughtsHow Lowering Capital Costs Affects Higher-Risk Loans
Government-sponsored enterprises (or GSEs) are companies that provide guarantees and financing to originators through the mortgage secondary market. The size and resilience of the GSE secondary market maximizes diversification and liquidity which reduces financial risk and cost of capital. This benefit accrues to conforming borrowers through lower mortgage rates and resiliently available financing.
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ProductsThe release of Andrew Davidson & Co., Inc.’s (AD&Co) new generation of financial engineering tools marks a shift to a new reality; when the traditional benchmark for MBS valuation, the LIBOR/ Swap yield curve, becomes unavailable. Our recent Product Release email informed our readers about the change. In short, our users can:
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ThoughtsFHFA held a listening session for interested parties on its proposed rule on the GSE process for credit scores. The objective is making mortgage underwriting and pricing more accurate and more fair while balancing practical implementation by firms in the mortgage ecosystem. Along with many others, I had the opportunity to provide insights on this proposed rulemaking.
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ThoughtsIn our January 19th blog entitled, A More Equitable Lending System Will Not Be Created by Accident, we described the efforts it will take to overcome not just bias in lending today, but the systemic factors that have limited access to credit in the past and have created an unjust system.
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ThoughtsIn this short blog post I discuss some developments taking place in the flood insurance landscape in the US and look ahead at a few potential directions things could go. I suggest that universal catastrophic flood insurance coverage with a continuation of the introduction of risk-based pricing would be a significant improvement.
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ThoughtsIntroduction
The Government-Sponsored Enterprises (GSEs) entered conservatorship in September 2008. One could view the succeeding thirteen years as a journey back to financial stability with a refined operating model that looks more like a financial utility than a hedge fund. This business model is more compatible with a fair lending mission for a standard-setter that maintains secondary markets under an effective regulator. The GSEs remain the largest part of the housing finance backbone and a resilient funding source during economic stress.
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Thoughts
Around 75% of white American families were homeowners in the first quarter of 2020, according to data from the United States Census Bureau. However, only 44% of Black American families owned their homes at the same time.
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Thoughts
According to a report by the Research Institute for Housing America, climate change risk is rapidly increasing in the housing industry and will continue to demand more attention and regulation in the near future.