About Us

OakBrook Investments is a research oriented firm driven by a group of professionals with advanced degrees in economics and finance. We have managed money since 1983, and previously worked as part of a team for one of the pioneers in index fund management and quantitative techniques.


OakBrook was formed in February 1998 and currently has three partners, Janna Sampson, Peter Jankovskis and Giri Cherukuri. Janna Sampson and Peter Jankovskis are OakBrook’s Managing Members and serve as Co-Chief Investment Officers. Giri Cherukuri is OakBrook’s Head Trader and a Portfolio Manager. Prior to OakBrook, the three worked together for several years managing portfolios at Northern Trust Quantitative Advisors and its predecessor, ANB Investment Management & Trust Company. OakBrook registered with the Securities and Exchange Commission as an investment adviser effective March 27, 1998, and began managing tax-exempt assets as of June 8, 1998.

From its initial launch with the Select Equity strategy and a single Enhanced Index strategy benchmarked to the S&P 500, OakBrook expanded its product lineup, adding additional benchmarks to the quantitative strategy family, and launched Small Cap and Global Select Equity strategies.

OakBrook Investments, LLC is 100% owned by employees.

Meet Our People

Portfolio Management, Research, and Trading
Meet Our Team

Meet Our TeamSeated (left to right): Giri Cherukuri, Peter Jankovskis.
Standing (left to right): Paula Mikrut, Janna Sampson.

Janna Sampson, CFA
Co-Chief Investment Officer

Janna Sampson In conjunction with Co-CIO, Peter Jankovskis, Janna is responsible for research, stock selection and portfolio construction related to the firm's investment strategies. She is a founding principal of OakBrook, is a significant shareholder, and is a member of the firm's Management Committee.

Prior to launching OakBrook, Janna was VP & Senior Portfolio Manager for ANB Investment Management & Trust Company, a $35B investment manager (now part of Northern Trust). In addition to her active involvement in managing assets for both the Select Equity and Enhanced Index styles, she was responsible for ANB's Balance Plus product line and an actively managed international equity mutual fund. Prior to joining ANB, she was a Research Analyst at Waldner & Co., a research boutique, and taught economics at College of DuPage.

Janna holds a BA in Economics and Political Science from University of Denver and an MA in Economics from Georgia State University. Janna is a CFA charterholder.

Peter Jankovskis, PhD, CFA
Co-Chief Investment Officer

Peter Jankovskis In conjunction with Co-CIO, Janna Sampson, Peter is responsible for research, stock selection and portfolio construction related to the firm's investment strategies. He is a founding principal of OakBrook, is a significant shareholder, and is a member of the firm's Management Committee

Prior to launching OakBrook, Peter was Head of Research for ANB Investment Management & Trust Company, a $35B investment manager (now part of Northern Trust). At ANB, Peter was actively involved in the management of the Select Equity style and an actively managed international equity mutual fund, the development of the quantitative model used for enhanced indexing and research in support of other investment strategies. Before joining ANB, Peter taught courses in finance, macroeconomics, microeconomics and industrial organization at University of California, Santa Barbara.

Peter received BS degrees, summa cum laude, in Computer Science and Mathematics, as well as his MA and PhD in Economics from University of California, Santa Barbara. Peter is a CFA charterholder.

Giri Cherukuri, CFA
Head Trader and Portfolio Manager

Giri Cherukuri Giri is Head Trader and Portfolio Manager. He is responsible for the execution of trades for all of OakBrook's strategies and is a member of the management team for all strategies. He joined OakBrook shortly after its launch and has worked with OakBrook's principals since 1994.

Prior to joining OakBrook in 1998, Giri was Investment Strategist at ANB Investment Management & Trust Company, a $35B investment manager (now part of Northern Trust). At ANB, he helped develop new investment strategies and manage index portfolios. Before joining ANB in 1992, Giri was a Data Analyst at Morningstar.

Giri received a BA in Economics, with Honors, as well as his MBA, from the University of Chicago. Giri is a CFA charterholder.

Paula Mikrut, CFA
Senior Researcher and Portfolio Manager

Paula Mikrut Paula Mikrut is a Senior Researcher and Portfolio Manager at OakBrook Investments, LLC. Paula is responsible for quantitative analysis and software development for research projects on current and new investment strategies. She also contributes to the fundamental research effort for Select Equity and is a portfolio manager. Paula is a member of the Investment Management team for all strategies.

Paula has an MBA from the University of Chicago, an MS in Computational Finance from DePaul University, and an MS in Computer Science from the University of Wisconsin-Madison. She is a CFA charterholder.

Tolga Guder, CFA
Research Analyst

Tolga Guder Mr. Tolga Guder is a Research Analyst at OakBrook Investments, LLC. Tolga provides support to portfolio managers, primarily focusing on equity research and idea generation. Tolga is a member of the Investment Management team for all strategies.

Tolga received a B.S. in Economics from DePaul University and a Post-Baccalaureate certificate in Finance from Northwestern University. He is a CFA charterholder.

Marketing and Client Service
David Vandergriff
Director of Marketing

David Vandergriff David Vandergriff is Director of Marketing at OakBrook Investments, LLC. Prior to joining OakBrook in February 2008, David was a Director of Institutional Sales at Allegiant Asset Management Company (AAMC), calling on corporate plan sponsors and nonprofit organizations. David held a similar position with Banc One Investment Advisors, Inc. before joining AAMC. At Banc One his sales responsibilities also included calling on public funds and Taft-Hartley plans. David sold commercial investment grade real estate prior to joining the institutional investment management industry. He earned a B.A. from Wabash College.

Jenny Deininger
Marketing Manager

Jenny Deininger Jenny Deininger is the Marketing Manager at OakBrook Investments, LLC. She is responsible for proposal management and development as well as strategic marketing, including market research, business plan and sales strategy development. Prior to joining OakBrook, Jenny spent more than nine years with Mesirow Financial, initially working in the fund-of-hedge funds group and then as part of the corporate marketing RFP team. She holds a B.A. in Journalism and English from Indiana University.

Cara Krug
Sales Director

Cara Krug Cara Krug is a Sales Director at OakBrook Investments, LLC. She is responsible for developing new business opportunities and maintaining relationships with clients and consulting firms. Cara has extensive experience in managing and protecting relationships with key clients, as well as coordinating and hosting appreciation events to strengthen customer loyalty. Her primary focus is responding to customer needs. Cara holds a B.S. from Illinois State University.

Debbie Burak
Client Administration Manager

Debbie Burak Ms. Debbie Burak is a Client Administration Manager at OakBrook Investments, LLC. Prior to joining OakBrook in 2005, Debbie was a Portfolio Administrator at Holland Capital Management, LP. Before joining Holland Capital, LP in 2002, Debbie was an Investment Analyst at Mercer Investment Consulting. Debbie received a B.B.A. in Finance from Benedictine University.

Shirley Fisher
Chief Compliance Officer

Shirley Fisher Ms. Shirley Fisher is the Chief Compliance Officer at OakBrook Investments, LLC. Shirley joined OakBrook in 2007. Prior to joining OakBrook, Shirley was the Assistant Treasurer/Controller at Northern Trust Investments, Inc. and was an Investment Officer in charge of Project Coordination at ANB Investment Management and Trust Company (“ANB”). Prior to joining ANB, Shirley held various Banking, Trust, and Investment positions with American National Bank and Trust Company in Chicago. Shirley received a B.S. in mathematics with minor in computer science from Benedictine University and a master’s degree, summa cum laude, in education from National-Louis University.

Annette Nestad
Office Manager

Annette Nestad Annette Nestad is the Office Manager at OakBrook Investments, LLC. She is responsible for organizing and coordinating office operations as well as assisting in various marketing functions. Prior to joining OakBrook, Annette was an Administrative Assistant at AmSouth Bank in Jacksonville, Florida. Annette began her financial career in 1991 and has since held various banking positions throughout the Chicagoland area and Jacksonville, Florida. Annette majored in Business Administration and Marketing at Lewis University.



Company News

January 2015: OakBrook Investments, LLC Becomes Corporate Sponsor of Women Investment Professionals

OakBrook Investments, LLC is proud to announce its corporate sponsorship of Women Investment Professionals (WIP), a professional women's organization that supports women in the institutional investment community. "As a majority female owned firm, OakBrook embraces WIP’s mission of providing professional and personal development opportunities, networking, and education programs to its members,” said Janna Sampson, Founding Member/Co-Chief Investment Officer of OakBrook Investments.

For more information on Women Investment Professionals, please visit www.wipchicago.org.


September 2014: Women Investment Professionals’ 2014 Trailblazer of the Year Recipient, Janna L. Sampson, CFA Co-Chief Investment Officer OakBrook Investments, LLC

Janna Sampson will be honored at the Women Investment Professionals’ (WIP) 8th Annual Trailblazer Dinner on October 16 at the University Club of Chicago. The Trailblazer Dinner is the pinnacle of the organization’s yearly programs, focusing on women who are inspirational in achieving professional and personal excellence. The Trailblazer of the Year award is given to a successful woman in financial services who has overcome obstacles, supports women in the community, and has an inspirational story to tell.

All candidate presenters were required to submit a nominee summary including background and reasons for nomination. Janna’s nomination was presented by a non-related third party and there were no financial agreements or transactions involved. A selection panel reviewed all submissions and voted on a winner. The award was not based upon any particular client experience or performance provided by OakBrook Investments.

Ms. Sampson is a CFA Charterholder, member of the CFA Society Chicago and the Chicago Finance Exchange (CFE), the Chicago area's preeminent group for women in finance. Ms. Sampson currently serves on the CFE's Philanthropy Committee working to provide financial education and support to disadvantaged women and girls in the Chicago area. She has also worked on the DuPage Habitat for Humanity Women Build project helping to provide housing for less fortunate women and their families in DuPage County, Illinois. In September 2014, she completed her third Avon Walk for Breast Cancer walking 39.3 miles to raise funds for breast cancer research and support. In her free time, Ms. Sampson loves to hike, ski, read and spend time in her native Colorado.

Ms. Sampson has been seen on ABC World News, Good Morning America, CNBC, Fox News, CBS MarketWatch, and Bloomberg News. She has been featured in Forbes, Money, The New York Times, The Washington Post, The Financial Times, The Chicago Tribune, Investment News and other publications.

For more information on Women Investment Professionals, please visit www.wipchicago.org.


February 2013: OakBrook celebrates 15 year anniversary.

Emerging Manager Award


Hammers and HeelsSeptember 2012: OakBrook Investments sponsored Hammers and Heels 2012, a Women Build project of DuPage Habitat for Humanity, whose goal is to provide simple, decent, and affordable housing in our community. A team of five - Debbie Burak, Janna Sampson, Wendi Svitak, Annette Nestad, and Paula Mikrut (left to right) - were part of a crew that is building 12 sustainable townhouses in Glen Ellyn, IL.

September 2011: OakBrook is ranked 39th largest manager of passive and enhanced index assets by Pensions & Investments in its September 19, 2011 issue (ranked by total worldwide assets managed internally as of June 30, 2011).

May 2010: Firm assets under management exceed $2 billion.

May 2010: OakBrook is named Equity Manager of the Year at the Opal Financial Group's 2010 Emerging Managers' Summit.

Emerging Manager Award In May 2010, Opal Financial Group held its Emerging Managers Summit and Awards Luncheon. OakBrook was a general sponsor of the event and participated in the award program.

The Emerging Managers Summit and Awards (EMSA) were open to companies or investment teams based in the US/Canada and Europe. All EMSA participants were required to complete an EMSA questionnaire. The judging panel was comprised of representatives from Emerging Manager Magazine, Opal Financial Group, and leading institutional and private investors. The award was not based upon any particular OakBrook client's experience or performance.

EMSAs were offered in 18 categories. The number of participants in each category was not disclosed. OakBrook submitted a questionnaire for consideration in two categories, Emerging Manager and Equity Manager, and won for Equity Manager. OakBrook's past performance may not be indicative of its future performance.


December 2009: OakBrook gains State of Illinois certification as Female Business Enterprise.

December 2009: OakBrook moves to new offices at 2300 Cabot Drive in Lisle, IL.


December 2008: OakBrook launches Quantitative Small Cap product.

February 2008: OakBrook celebrates 10 year anniversary.

OakBrook Tenth Anniversary

January 2008: Janna Sampson becomes majority owner. Giri Cherukuri becomes an owner and joins the investment committee.


December 2007: OakBrook acquires 49% ownership interest of Regions Bank and becomes 100% employee-owned.

September 2007: Neil Wright retires as CIO, Fundamental Products; Janna Sampson and Peter Jankovskis become Co-CIOs of OakBrook Investments.

November 2003: Firm assets under management exceed $1 billion.

August 2002: Firm assets under management exceed $500 million.

June 2002: OakBrook Market Neutral Fund, LP launched. OakBrook Enhanced Mid-Cap launched.

September 2000: First expansion of Enhanced Index benchmarks - Enhanced Large Cap Value launched. The launch of an additional benchmark begins the process of adding benchmarks that has continued over time.
OakBrook Investments founded by Janna Sampson, Peter Jankovskis, and Neil Wright with two products: Enhanced Index and Select Equity.