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.

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Blog - Latest
  • 2026 Cultural and Volunteer Day

    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.

    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.

    AD&Co filling backpacks with essential school supplies for K-12 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.

    AD&Co participating in the Save Ellis Island's Hard Hat Tour.

    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.

  • Now Available: AD&Co’s Quantitative Perspectives

    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.

    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.

    READ NOW

    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.

  • AD&Conversations: Trends in the Home Equity Sector

    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 release of our much-anticipated industry HELOC model.

  • Industry Leaders in Fixed-Income Analytics, Kelli Sayres and Gene Park, join Andrew Davidson & Co., Inc. 

    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. 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.

    READ NOW 

     

  • White Paper: Evaluating GSE Servicing Rights With Extended Consumer Credit Data: Valuation and Sensitivity Analysis

    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.

    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

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