Advisory Team

Get to Know Us

CFP® practitioners. Super-smart. Widely published. Modest. Really nice, too.

  • Andrea N. Eaton, M.S.,CFP®

    Andrea N. Eaton, M.S.,CFP®

    Financial Planner

    Andrea is a Principal and Financial Planner at Cornerstone and likes to think of herself as a financial planning mentor to the clients of Cornerstone. She began her career as a Graduate Intern in 2004 and has been at the firm full-time since 2005. Andrea enjoys getting to know the clients of Cornerstone personally and knowing them is key to helping them reach their financial and life goals.

    Andrea graduated from South Dakota State University where she earned a Bachelor’s Degree in Human Development and Family Studies. Wanting to combine her quantitative ability with the desire to help people, she was drawn to financial planning. She attended and graduated from Texas Tech with a Master’s degree in Financial Planning.

    Andrea is a member of the Financial Planning Association, keeping her up-to-date with the ever changing financial world. She is also a CERTIFIED FINANCIAL PLANNER™ professional. Andrea has been involved in writing and reviewing questions for the CFP® Comprehensive Exam. She also prepares and reviews individual income tax returns for the clients of Prepare + Prosper (formerly AccountAbility Minnesota), a nonprofit serving the tax needs of Minnesotans with low incomes.

    Andrea grew up in Sioux Falls, South Dakota and married a fellow South Dakotan, Michael. They now live in Bloomington with their daughter, Luella and feline friend, Chester. In her spare time, she enjoys cycling, walking, going to the gym, exploring Minnesota, South Dakota, and other places near and far, reading, and spending time with friends and family.

  • Jonathan T. Guyton, CFP®

    Jonathan T. Guyton, CFP®


    Jonathan is Cornerstone’s Principal and is recognized as a thought leader in the financial planning profession for his holistic work in the art and science of retirement planning. His specialties include retirement income planning and investment management with an emphasis on asset distribution and income tax planning.

    Jon is best known as the author of “Decision Rules and Portfolio Management for Retirees: Is the ‘Safe’ Initial Withdrawal Rate Too Safe?”, published in the October 2004 Journal of Financial Planning and a winner of its national Call For Papers competition. He also co-authored “Decision Rules and Maximum Initial Withdrawal Rates” with computer scientist William Klinger in its March 2006 issue. Jon was named one of ’15 Transformational Advisors’ of the past twenty years in 2013 by the readers of Investment News. He currently serves as a retirement planning columnist for the Journal of Financial Planning; his recent columns appear in the Our Publications section of this site. He is also an Expert Panelist on Retirement for the Wall Street Journal and an Online Columnist for Time and Money. Jon is regularly quoted in the New York Times, USA Today, Forbes, Business Week, Research, and Kiplinger’s Personal Finance. He has been honored to make numerous presentations to literally thousands of colleagues based on his published writings and work with clients.

    Jon graduated Phi Beta Kappa from the College of William and Mary in Virginia in 1983 with a B.A. in Economics and spent five years as a financial planner and national training officer for Ameriprise Financial (then IDS) before creating his own firm in 1990. He earned his CERTIFIED FINANCIAL PLANNER™ certification in 1989. His professional accomplishments include:

    • National Board of Directors, Financial Planning Association (FPA) (1999 – 2002)
    • Dean and Mentor, FPA Residency for New CFP® Practitioners (2003 – Present)
    • Chairman and Dean, 1999 National CFP® Masters Retreat (Lake Tahoe, CA)
    • Program Committee, 2004 FPA Convention; 2006 FPA Retreat; 2007 FPA Retreat
    • Chair, FPA Career Development Strategic Team (1999 – 2006)
    • Author, “Blazing Financial Planning Career Paths,” Journal of Financial Planning, 1999

    Jon has lived in the Twin Cities since 1987 and is an Eagle Scout. His hobbies include choral singing, baseball, cycling, wine collecting (and the sharing thereof) – nearly all of which he enjoys best with his wife.

  • Sara Kantor, CFP®

    Sara Kantor, CFP®

    Financial Planner

    Sara Kantor is a Financial Planner at Cornerstone and a graduate of Cornerstone’s three-year Residency program. Her CERTIFIED FINANCIAL PLANNER™ coursework was through the University of Georgia – Terry School of Business and she completed the final requirements for her CFP® certification in 2016. She previously earned a Bachelor of Music in Music Education and Masters of Music in Voice Performance at the University of Minnesota – Twin Cities. Sara is an active member of the Financial Planning Association (FPA) and past president of FPA of Minnesota.

    She has maintained a private vocal studio for over twenty years and worked with her husband at their brand strategy consulting firm, KantorGroup, for five years. Her years of experience and passion for helping others gain clarity, combined with her client and business management skills, piqued her desire to help others in their personal lives through financial planning.

    Sara was raised in rural west-central Minnesota, where her parents still reside. She and her husband, Dan, live in Bloomington and enjoy home and garden projects, nurturing their two rescue kitties Leo & Nellie, traveling, sharing their love of music together, and taking in the local dining scene.

  • Coresa Leighty, CFP®

    Coresa Leighty, CFP®

    Resident in Financial Planning

    Coresa joined the Cornerstone team as our Client Service Associate in October 2015. She earned her Bachelor’s Degree in Chemistry and Spanish at the University of Minnesota – Morris in 2009. After working six years as an Analytical Chemist, Coresa enrolled in a CFP® Board-Registered Program with the Terry College of Business at the University of Georgia in 2014. In addition to her new role and new career, she also became a member of the Financial Planning Association of Minnesota.

    Alongside the Cornerstone team, Coresa assists in helping our clients meet their unique goals and objectives all while achieving her own. She is most eager to help people from all walks of life while enhancing her skills in comprehensive financial planning.

    A native of New Ulm, Minnesota, Coresa enjoys spending a majority of her time outdoors with her fiancé, Abe. When she is not catering to her Great Dane, Zoey, she also enjoys spending time with family and friends, trips to the cabin, and exploring the Twin Cities.

  • Christina Tucker

    Christina Tucker

    Client Service Associate

    Christina is Cornerstone’s Client Service Associate. She earned her Bachelor’s Degree at the University of Minnesota in 2013 in Art History (summa cum laude), with minors in French and Medieval Studies. After graduating, she worked at a financial firm in Minneapolis and then transitioned in 2014 to Vision Loss Resources, a local Twin Cities non-profit. There, she most recently held the position of Program Coordinator for Community Services. She joined the Cornerstone team in May 2018.

    Aiming to provide exceptional service, Christina assists the Cornerstone team by attending to details, such as scheduling, assisting clients with forms, and other support tasks. She is eager to help and loves getting to know people and learning about their passions and unique outlooks on life.

    Christina is a local Minnesotan who grew up in Bloomington and now lives in Minneapolis with her husband, Nate and two fluffy cats, Artemis and Freya. She thoroughly enjoys experimenting with various art and painting styles, playing the harp, working on DIY projects, and finding new food spots with friends and family in the Twin Cities.