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
  • Diversity Awareness Lifts all People

    AD&Co Marketing Team

    Thoughts

    To seek "causes" of poverty in this way is to enter an intellectual dead end because poverty has no causes. Only prosperity has causes. – Jane Jacobs, Activist and Author

    Here at Andrew Davidson & Co., Inc. (AD&Co) we have been aware since our founding in 1992 that diversity of all kinds makes for a more interesting culture, a better exchange of ideas, and ultimately better products and services. However, for all of us, globally and in the U.S., there is still a long way to go. We are focused on increasing our sensitivity to diversity and unconscious bias and have made diversity outreach in recruiting, mentorship, vendors, charitable giving—indeed, in every aspect of our business a priority. We have been focused on the fact that every person deserves an equitable life. Our guiding principle is that we are all people and we all deserve to be treated equally. 

    This is especially relevant to issues of housing as AD&Co’s Richard Cooperstein has addressed in the article he co-authored with Ken Fears from the National Association of Realtors (NARS) and Susan Wachter of the Wharton School for Business, University of Pennsylvania, Government-Sponsored Enterprises: Their Viability as Public Utilities published in the journal “Housing Policy Debate,” Volume 31, 2021 - Issue 1: The Mortgage Market in the Time of COVID / Smart Cities, Housing, and Community Development Policy.

  • Listen To Freddie Mac's Interview With Andy Davidson On Their Inaugural Single-family Podcast

    AD&Co Marketing Team

    Events

    CRTcast, a new podcast series under Freddie Mac’s Home Starts Here programming, focuses on credit risk transfer (CRT) and it’s three spokes: securities, (re)insurance and mortgage insurance. Freddie Mac leadership together with CRT industry experts cover current and relevant topics.

    In the inaugural episode, Single-Family CRT Vice President Mike Reynolds sits down with Andrew Davidson & Co., Inc, (AD&Co) founder Andy Davidson to talk all things risk intelligence,  including planting the seeds of a GSE CRT market in 2010; and connecting with Freddie Mac to launch the first GSE CRT securities transaction in 2013. 

    Click here to listen to the podcast. 

    About Freddie Mac Single-Family Credit Risk Transfer

    Freddie Mac’s Single-Family CRT programs transfer credit risk away from U.S. taxpayers to global private capital via securities and (re)insurance policies. The GSE Single-Family CRT market was founded when Freddie Mac issued the first STACR® (Structured Agency Credit Risk) notes in July 2013. In November 2013, ACIS® (Agency Credit Insurance Structure was introduced. Today, CRT serves as the primary source of private capital investment in residential mortgage credit. For specific STACR and ACIS transaction data, please visit Clarity, Freddie Mac’s CRT data intelligence portal.

  • Richard Cooperstein named co-chair of the Structured Finance Association’s Regulatory Capital & Liquidity Committee

    AD&Co Marketing Team

    News

    We are proud to announce that Richard Cooperstein has accepted the position of co-chair of the Structured Finance Association’s (SFA) Regulatory Capital & Liquidity committee. 

    “I am very pleased to be chosen to co-lead SFA’s Committee that is focused on rationalizing risk transfer for federally-connected institutions.  Aligning the regulation of risk transfer with the economics can improve capital efficiency, lower borrowing costs and reduce taxpayer risk.” - Richard Cooperstein

    SFA plays an essential role in Structured Finance by bringing thought leaders together to collaborate on ways to respond to timely events affecting the industry, finance and our world.

  • Andrew Davidson & Co., Inc. Celebrates Lunar New Year

    AD&Co Marketing Team

    News

    Today we acknowledge the Year of the Ox. Happy Lunar New Year! We stand in solidarity with the Asian community against all violence and racism. Here’s to a year of peace, health and prosperity.

    Lunar New Year

  • Andrew Davidson & Co., Inc. Celebrates Black History Month

    AD&Co Marketing Team

    News

    This February, AD&Co celebrates a central part of American History—Black History. The richness of the contributions of the Black community as a whole, and innumerable remarkable individuals, can not be overstated.

    AD&Co Celebrates Black History Month

     

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.