BB web bg leadership.png


Bill Horne.jpg

Bill Horne

Chief Executive Officer

Bill has more than 25 years of C-Suite experience across many companies, focusing on fintech, transaction processing, SaaS, and software development and healthcare services. Bill has been associated with Sopris Capital since 2004 and most recently served as Chairman and CEO of Quovant since 2015 which was sold to Mitratech in 2022. Bill sold Healthcare Data Solutions to IMS Health in 2015, where he served as Chairman, President and CEO. He was previously President and CEO of Truist in 2009, which was sold to Alta Equity Partners in 2012 and again to FrontStream Payment Systems in 2014. From 2007 through 2009, Bill was Managing Director at Sopris Capital Associates. In 2004 Bill served as President and Chief Executive officer of Valutec that was sold to Metavante in 2007. Prior to 2007, Bill served in various executive leadership positions at First Data and IBM. He holds a B.S. in Business Administration from California Polytechnic State University, San Luis Obispo, and serves as a director on multiple boards.

Maegen Pierce (3).jpg

Maegen Pierce, M.A. BCBA, LBA

Founder & Chief Visionary Officer

Maegen founded Breakthrough Behavior with the mission to provide highly effective and accessible services to individuals with autism. She has grown the national organization to more than 400 employees across 10 facilities in Florida, California, Virginia and Maryland. As a board certified behavior analyst (BCBA) with more than fifteen years of experience in the applied behavior analysis field, she has specialized in school, clinic and home therapy, providing a unique and personalized treatment plan for hundreds of clients throughout the United States. Maegen received her bachelor's degree in psychology with an emphasis in applied behavior analysis (ABA) from California State University, Fresno and master's degree in special education from California State University, Monterey Bay. Maegen is a member of the American National Standards Institute (ANSI) Commission for the Behavioral Health Center of Excellence (BHCOE), the Central Florida Political Leadership Institute (PLI) 2020 Class, and the League of Women Voters of Orange County. She has also served as Chair of the MAGIC program with the Junior League of Greater Orlando, Chair of the Provider Connection Committee with Autism Speaks and a coach with the Special Olympics. She also currently serves on the Breakthrough Behavior Board of Directors. Maegen was named a “40 Under 40” award honoree by the Orlando Business Journal. She currently resides in Orlando, Florida, with her husband Ryan, daughters Saoirse and Ella, and goldendoodle Charlie.

Nicole McMillan_edited.jpg

Dr. Nicole McMillan, PhD, BCBA-D

Chief Clinical Officer

Dr. McMillan has dedicated her professional life to the science and practice of ABA, first engaging in the field while pursuing her undergraduate degrees in communication sciences and disorders and psychology at Louisiana State University. In 2015, she graduated with her doctorate in cognitive and behavioral Sciences with an emphasis in ABA from Auburn University. Dr. McMillan has excelled in roles across several facets of business operations and clinical management, particularly in quality assurance development and maintenance, clinical team mentorship, community outreach, executing clinically relevant research projects, university program partnerships, and training and professional development. Her passion lies with service excellence and ensuring that families are receiving the highest quality services possible from intake through graduation. She believes strongly in a scientist-practitioner model and incorporating best practice guidelines into all levels of service delivery and clinical training. Dr. McMillan currently resides in St. Petersburg, Florida, with her husband and daughter. She enjoys the beach, outdoor festivals, hot yoga, cooking, and most importantly, spending time with her family.


Christie Penland, M.Ed., Ed.S., BCBA

Chief Operations Officer

Christie directs and oversees the financial and operational performance of all lines of business for Breakthrough Behavior. Christie has more 20 years of experience in the applied behavior analysis (ABA) field including both clinical and operations. She began her career as a direct therapist and, after obtaining her master’s degree from the University of South Carolina, went on to complete her coursework through the Florida Institute of Technology to become a board certified behavior analyst (BCBA). For more than a decade, she practiced as a BCBA with a focus on providing high quality ABA programs to children on the autism spectrum as well as supporting and mentoring clinicians into leadership positions. During her experience in overseeing operations for multiple markets across several states, Christie developed, monitored and executed key performance indicators to ensure successful financial outcome while maintaining a high standard of care. Christie is married and has two daughters ages six and ten, as well as a large fur baby who keep her quite busy.

Elliott Chester.jpg

Elliott Chester

Chief Financial Officer

Elliott is a seasoned finance expert and executive. He was the CFO of a 350-bed, multi-site regional behavioral health organization and has held roles as interim CFO for two private equity-backed startups. Prior to that, Elliott worked in forensic accounting and litigation support in public accounting, FP&A and internal audit at a Fortune 500 telecom organization, and served in various analytics and finance roles at another Fortune 500 digital marketing firm. Elliott has also served as a subject matter expert and author for Becker Professional Education, co-authoring their CPA and CMA exam prep textbooks and writing courses on various accounting subjects. He has also taught tax, finance and accounting courses at Southern New Hampshire University. Elliott holds a bachelor’s degree in business administration, an MBA, and a master’s degree in operations management and industrial engineering. He is a Certified Public Accountant, Certified Management Accountant, and Certified Fraud Examiner.