ESS Board of Trustees

Leonard M. Rush

Lead Independent Trustee, Audit Committee Chair

Len Rush has served in several different senior executive roles at various global financial services firms. Most recently, Mr. Rush served as Managing Director and the Chief Financial Officer of Baird, Baird Holding Company, Baird Financial Corporation and is the Treasurer for Baird Funds. Prior to joining Baird in 2000, Mr. Rush spent nine years at Fidelity Investments, where he was CFO of its four broker dealers, Vice President/ Head of Compliance and Assistant Treasurer for the funds. Prior to Fidelity, Mr. Rush was a Vice President at Credit Suisse First Boston, a Manager with Goldman, Sachs & Co. and a Senior Manager with Deloitte & Touche. Mr. Rush holds a BBA, with a focus in Accounting, from the University of Wisconsin-Madison and a Masters of Business Administration from New York University. Mr. Rush is also a Certified Public Accountant.

David Massart

Independent Trustee

David A. Massart is a co-founder, Chief Investment Strategist and President of Next Generation Wealth Management, Inc., a SEC registered investment advisory firm. Mr. Massart has 18 years of financial experience working with high net worth individuals, families, trusts and retirement accounts. David’s responsibilities include: setting the firm’s overall strategy, strategic and tactical asset allocation decisions, investment manager evaluation/selection and client relationship management. He is the lead member of Next Generation Wealth Management’s Investment Committee. Prior to co-founding Next Generation Wealth Management, Mr. Massart was a Manager at Wells Fargo Investments, LLC and a Managing Director of Strong Private Client. With David’s leadership and entrepreneurial spirit, he was responsible for building a wealth management team that managed over $275 million in client assets. Mr. Massart has been a featured presenter on a broad range of wealth management issues, including asset allocation, portfolio design, tax aware investment strategies and implementation of investment best practices over the past eighteen years. Mr. Massart holds an undergraduate degree in Business Management from the University of Minnesota where he was awarded a varsity tennis scholarship, receiving a Bierman Academic Scholar for 3 consecutive years. Mr. Massart’s team won two Big Ten Men’s Tennis Championships and was selected by his teammates as a co-captain during his senior season. Mr. Massart co-founded Next Generation Philanthropy, LLC and is the founder of Next Generation Entrepreneurs Group. Mr. Massart serves on several advisory boards in Wisconsin.

Janet D. Olsen

Independent Trustee

Ms. Olsen has substantial industry experience, including over a decade serving as a senior executive of an investment management firm and a related public company, as well as an executive officer of another investment company from 2001 to 2012. Ms. Olsen most recently served as Managing Director and General Counsel of Artisan Partners Limited Partnership, a registered investment adviser serving primarily investment companies and institutional investors, and several affiliated entities, including its general partner, Artisan Partners Asset Management Inc. (NYSE: APAM), and as an executive officer of Artisan Funds Inc.

Mike Castino

Interested Trustee

Mike Castino serves as business development officer for the Exchange Traded Funds and Unit Investment Trusts division. Mr. Castino joined U.S. Bancorp Fund Services in 2013 with more than 20 years of business development, relationship management, marketing, managerial experience,and futures/equity trading experience. Prior to joining U.S. Bancorp Fund Services, Mr. Castino worked for Zacks Investment Management as managing director of the Index Services Division. He also held the position of vice president of Institutional Sales for Claymore ETFs (now Guggenheim Funds) and was senior floor trader at the Chicago Mercantile Exchange for a major Wall Street trading firm. Mr. Castino received his Bachelor of Arts degree in business management from Illinois State University and is Series 7 and 66 licensed.

Kristina Nelson


Kristina Nelson serves as fund administrator for a select group of mutual fund and ETF clients. Kristina manages a team responsible for SEC filings, board materials, distributions, monitoring fund compliance as well as assisting in the overall accounting and operations of the funds. Kristina currently also serves as the president for ETF Series Solutions, a Multiple Series Trust complex serviced by Global Fund Services. Kristina has more than 15 years of experience in accounting and financial reporting. Prior to joining U.S. Bank in 2010, Kristina was a senior assurance associate with Grant Thornton. Kristina received her Bachelor of Arts in accounting and information systems from Carthage College.

Isabella K. Zoller


Isabella K. Zoller serves as assistant vice president and is a member of the Regulatory Administration team. Isabella provides counsel on the Investment Company Act of 1940 and related securities laws. Isabella joined U.S. Bank in May 2018. She has a comprehensive understanding of open-end fund registration statements and disclosure requirements and is particularly knowledgeable about exchange traded funds (ETFs). Isabella serves as a resource for clients and internal compliance administrators.

Isabella earned her Bachelor of Arts in Communication and her Bachelor of Arts in Spanish, each with distinction, from Indiana University. She later earned her Juris Doctor, cum laude, from Marquette University Law School. In law school, Isabella served as an associate editor of the Marquette Law Review.

Kristen Weitzel


Kristen Weitzel, CPA, serves as fund administrator for a select group of clients. She was a project manager on the establishment of exchange-traded fund servicing at Global Fund Services and is now a member of the ETF Fund Administration team. Additionally, Kristen serves as an officer of ETF Series Solutions, a series trust organized by Global Fund Services. Kristen has more than 12 years of experience in the financial services industry. Prior to joining U.S. Bank in 2011, Kristen was an audit manager with PricewaterhouseCoopers, specializing in auditing and assessing the internal control structure of regulated investment companies, hedge funds, broker-dealers and other financial services organizations. Kristen received her Bachelor of Business Administration and Master of Accountancy degrees from the University of Wisconsin Madison.

Liz Scalf


Liz Scalf, JD, CAMS, serves as chief compliance officer of ETF Series Solutions and previously served as the CCO for Trust for Professional Managers, each a multimanager series trust serving unaffiliated advisers. As a member of the Regulatory Support Services team, Liz manages the team of MST CCOs and assists with various compliance projects. She has over 10 years of experience in the investment management industry. Prior to joining U.S. Bank in 2017, Liz served in various legal and compliance capacities with Heartland Advisors and its proprietary mutual fund complex, Heartland Group. Her positions included chief compliance officer of Heartland Advisors and Heartland Group.

Liz earned a Bachelor of Business Administration in finance and marketing from the University of Wisconsin Oshkosh and a Juris Doctorate from Marquette University Law School. Liz is a licensed attorney and member of the State Bar of Wisconsin. She is a member of the Investment Company Institute AML Working Group. Liz also helped create, and is a Steering Committee member of, the Milwaukee Compliance Roundtable.