David Jaffe, MD

President

David is a partner and President of Professional Advisory Services, Inc. and serves on the Board of Directors. After attending Dartmouth College and the University of South Florida Medical School, he established a medical practice in Pulmonary Disease and Critical Care Medicine. In 1992, David left the practice of medicine to become a Portfolio Manager at PASI, becoming President in 2004. David is actively involved in portfolio management and investment decisions, advises clients regarding retirement plan options, and travels extensively to visit with clients around the country. During personal time, David enjoys fly-fishing and downhill skiing, leading him to the 2015 purchase of a home in Bozeman, MT.

Carol Bieber

Vice President

Carol is a partner and Vice President of Professional Advisory Services, Inc. and serves on the Board of Directors. As a corporate officer, her responsibilities include Secretary, Treasurer, HR, and Chief Compliance Officer. Carol graduated from the University of Florida with a Bachelor’s degree in 1982 and joined PASI in 1998. Carol is a Portfolio Manager and enjoys working with a diverse client base including attorneys, CPAs, physicians, and retirees. The majority of her time is dedicated to client relationships and overseeing the management of retirement and personal accounts. In her free time, Carol loves boating along the Indian River and traveling, but most of all, spending time with her family.

Nathan Polackwich, CFA^®

Senior Equity Analyst

Nathan graduated from Tulane University in 1998 with a Bachelor’s of Science in Economics. He has held the Chartered Financial Analyst (CFA^®) designation since 2004. Nathan started with PASI in 2001 and is now the firm's senior equity analyst leading development of PASI investment strategy including complete top-down analysis from the macro-economy to the individual company level. Nathan is also the Senior Municipal Bond Manager, serves on the Proxy Committee, and heads up PASI's Research Team and Investment Committee. In addition to writing for the PASI Newsletter, Nathan is the author of In Context – How the Challenger Disaster, Black Swans, and Collapsing Sand-Piles (Among Other Phenomena) Are Connected and What They Tell Us About the Stock Market. In his free time Nathan enjoys spending time with his wife and two sons and is passionate about surfing and composing music.

Christopher Brown, MBA

Portfolio Manager & Equity Analyst

Chris graduated from Rollins College in 1993 with a Bachelor’s in Economics and went to work on Wall Street for Investment Bank, Donaldson, Lufkin, & Jenrette as a Portfolio Assistant in equity derivatives. In 1999-2000, he went on to earn his MBA in Finance/Accounting from Tulane University. Chris joined PASI in 2001 as a Portfolio Manager and Equity Analyst. In addition to management of client portfolios, he is also the Senior Corporate Bond Manager and serves on the Proxy Committee and Research Team. Chris is the father of three and has traveled extensively with his wife and children to places such as Africa, Iceland, and the Galapagos Islands. Chris enjoys playing tennis and is an avid fisherman who often competes in local tournaments.

Chris Steele, CFP^®

Portfolio Manager

Chris graduated from the University of Central Florida in 1998 with a Bachelor’s degree in Finance. He worked at UBS Financial Services as a financial advisor for six years, actively managing equity and fixed income portfolios for clients. In 2004-2005 Chris attended the University of Central Florida Financial Planning Certificate Program and earned his CFP^® designation, solidifying his expertise in areas such as retirement, tax, insurance, and estate planning. Chris joined PASI in 2007 as a Portfolio Manager focusing the majority of his time on client relationships and portfolio management of retirement and personal investment accounts. Additionally, he serves on the Proxy Committee and Research Team. In his free time, Chris enjoys playing ball with his son as well as surfing, golf, and racquetball.

Jordan Bieber, CRPC^®

Portfolio Manager

Jordan graduated from Stetson University in 2014 with a Bachelor’s of Business Administration in Finance. He worked for Merrill Lynch as a financial advisor for three years, actively managing equity and fixed income portfolios for clients. In 2017 Jordan earned the professional financial designation of Chartered Retirement Planning Counselor^SM, CRPC^® from the College of Financial Planning. Jordan joined PASI in 2018 as a Portfolio Manager, focusing his time on client relationships and portfolio management for retirement and personal investment accounts. In addition to the management of client portfolios, Jordan is also a contributing member of the Proxy and Investment Committees. In his free time, Jordan enjoys playing golf and tennis.

Jeremy Goldberg, CFA, CFP^®

Portfolio Manager and Research Analyst

Jeremy graduated from Stetson University in 2014 with a Bachelor’s of Business Administration in Finance, with a minor in Statistics. In 2015 he earned his Master of Science in Finance (MSF) degree from Olin Business School at Washington University in St. Louis, Missouri. Jeremy joined PASI in 2018 as a Portfolio Manager and Research Analyst, and that same year earned the Chartered Financial Analyst (CFA®) designation. He completed the program to become a CERTIFIED FINANCIAL PLANNER^TM Professional in 2022.

In addition to the management of client portfolios, Jeremy is also a contributing member of the Proxy Committee, Investment Committee, and Research Team. Prior to joining PASI, Jeremy worked as an Investment Associate at Mozaic, LLC, and as a real estate investment trusts (REITs) Equity Research Associate at Raymond James & Associates. In his free time, Jeremy enjoys spending time with his wife and daughter, and loves cooking, music, and sports.

Donald Sienkiewicz, JD, CFP^®

Portfolio Manager

Donald H. Sienkiewicz grew up in Washington, D.C. He earned bachelor's degrees in Economics and Environmental Policy at Boston University, followed by a Juris Doctor degree at Northeastern University Law School. While an undergraduate in Boston, he met German native Katja Hock. They married shortly after Donald’s college graduation, and together raised four children in a small town in New Hampshire.

Donald practiced law in Massachusetts and New Hampshire from 2002 to 2024, focusing on commercial real estate transactions in the first half of his legal career, and trusts and estates during the second half.

In 2020 Donald shifted focus to financial services and broadened his skill set, earning certification as a CERTIFIED FINANCIAL PLANNERTM Professional. Donald joined the investment team at Professional Advisory Services in April 2024.

Donald loves to fish, sail, and do almost anything that involves being outdoors in nature.