William Lee is an associate with the Banking & Finance team. William represents issuers, underwriters, lenders, mortgage servicers, investment banks, investors, funds and rating agencies in the securitization and financing of various classes of assets in the structured finance market.

William is Mayer Brown’s 2022 Pro Bono Associate of the Year. He is a Vice-Chair of the Asian-American Bar Association of New York (AABANY) Student Outreach Committee and founded its “Student Leaders” and “Students Meet Mentors” programs. William regularly speaks at law school functions, was featured as a distinguished panelist for Columbia Law School APALSA’s 2021 Annual Conference “Writing Your Own Script,” and co-supervised Columbia Law School and AABANY’s first and second Student Pro Bono Caravans.

William additionally organized and moderated a small-business COVID-19 relief presentation series. He also created AABANY’s Pro Bono Student Task Force and has been instrumental in leading COVID-19-related web content, social media and door-to-door campaigns. William was a frontline volunteer for the Korean Community COVID-19 Pro Bono Hotline, which was composed of six attorneys who provided SBA loan, unemployment and mortgage relief to over six hundred Korean speakers. William today works against anti-Asian violence with his students.


  • Represented iBuyers, start-ups, funds and alternative asset managers as borrowers and investment bank as lender on their respective SFR warehouse financings ranging from $50 million - $1 billion, many of which involve mortgages on Day 1.
  • Represented 10+ investment bank lenders on their respective warehouse facilities involving EBO, fix-and-flip, nonperforming, re-performing, Agency, and non-QM residential mortgage loan collateral ranging from $50 million - $1+ billion.
  • Represented a private investment banking company and multiple mortgage loan originators on their respective non-QM securitizations as sponsor and issuer’s counsel totaling $2+ billion.
  • Represented a specialty financing company and real estate investment and development firm on their respective SFR and fix-and-flip securitizations.
  • Represented various clients on their mortgage servicing right financings including: representation of sponsor and issuer in the securitization of Agency servicing advance receivables; representation of borrower in a seller financing of Fannie and Freddie mortgage servicing rights; representation of sponsor and issuer in a master trust structure for the financing of Ginnie mortgage servicing rights; and representation of an investment bank in the structuring, negotiation, and issuance of variable funding notes and term notes backed by Ginnie mortgage servicing rights and the related $500 million excess spread.
  • Represented borrower in a $30 million repurchase agreement backed by a debtor-in-possession loan and lender in a bespoke warehouse facility structure backed by $100 million of SBA 504 loans.
  • Represented the initial purchasers in the issuance of unsecured and nonguaranteed notes, some of which were issued through Freddie Mac’s Structured Agency Credit Risk program.
  • Represented Ginnie Mae in its capacity as guarantor in the securitizations of single-family and reverse-mortgage loans.
  • Represented a lender with renewals and amendments for 15+ repurchase facilities backed by billions of dollars of residential-mortgage loans.
  • Represented a rating agency in Dodd–Frank compliance matters.


New York University School of Law, JD

Cornell University, BA


  • New York
  • Not admitted in California. Practicing under the supervision of firm principals.


  • National Asian Pacific American Bar Association (“NAPABA”)
  • Asian American Bar Association of New York (“AABANY”)

    • Student Outreach Committee, Co-Chair (former), Vice-Chair (current)
    • Student Leaders Program, Founder and Director
    • APALSA Roadshow Program, Speaker
    • Legal Referral Information Service, Committee Member (former)
    • Pro Bono and Community Service, Committee Leader

  • Represented NAPABA and AABANY at the 2021 Collaborative Bar Leadership Academy
  • Columbia Law School APALSA 2021 Annual Conference: “Writing Your Own Script”, Distinguished Panelist
  • Korean American Lawyers Association of Greater New York, Member