Tomahawk, WI Office: Our Team

Tomahawk, WI Office: Our Team

Randy Plantenberg

Wealth Advisor, Tomahawk Office

With more than 35+ years' experience managing client portfolios, Randy is a fee-based wealth advisor committed to providing a proactive investment management process for clients. This process includes defining client goals, values, and tolerance for risk and then creating a definable risk management plan. The use of technical analysis is a discipline that defines when to be fully invested, or, more important, when to reduce exposure to the equity markets. This level of commitment is why clients truly understand and believe that Randy has their best interests at heart. His ongoing priority is to create a level of performance and service that exceeds client expectations.

Randy began his career with E.F. Hutton & Company as a financial advisor in Tucson, Arizona, recognizing the many changes taking place within the financial services industry. Randy joined Dain Rauscher as vice president in 1992. He made the decision to move his family back home to Wisconsin in 1999, where he is the founder of MainStreet Investment Group LLC.

He is a wealth advisor with Commonwealth Financial Nework®. As an independent fee-based wealth advisor, Randy selects only those investment opportunities that are appropriate to his clients' best interests.

Randy and his wife, Lollie, reside in Tomahawk, Wisconsin, and have three sons, Brody, Jason, and Cory, and two grandsons, Landon and Jordan. Away from the office, his interests include spending time with his family, bow hunting, and fishing. 


Randy Plantenberg is proud to have been recognized as a Summit Club advisor for 2018—a distinction based on annual production that places him among the top 22 percent of advisors affiliated with Commonwealth Financial Network. 

Each year, Commonwealth, the broker/dealer–RIA that helps us process investment transactions on your behalf, recognizes Summit Club advisors by inviting them to an exclusive gathering of their peers, leading industry experts, and Commonwealth home office staff. Summit Club advisors benefit from an intensive learning and networking experience designed to help them hone their expertise, share best practices, and provide ever-higher levels of service, education, and leadership to their clients.

Sara Olsen

Wealth Management Associate, Tomahawk Office

Sara joined MainStreet Investment Group in August, 2014 as our Operations Manager.  In 2015, Sara successfully completed the Series 7 and Series 66 licensing exams.*  Sara is now our Wealth Management Associate, where she provides technical support to Randy centered on the principals of integrity, superior client service and ethical business practices.  Her passion for honesty, hard work, respect, and consistent and thorough communication create a very comfortable working relationship with our clients.  Sara is committed to acting in the best interest of clients and is able to offer an array of services including implementation and maintenance of Financial Plans, monitoring asset allocations, research and helping our clients with any needs or questions that may arise.

Prior to joining MainStreet Investment Group, Sara worked at Fox Networks as an Executive Office Coordinator in Los Angeles, California.  Sara made the decision to relocate back home to Tomahawk, where she and her husband, Steve, now reside with their son, Bodie, who is an active eight year old involved in baseball, wrestling, waterskiing and master Lego building.  In her free time, she enjoys watching Bodie in his activities, waterskiing, snowmobiling and during football season you’ll find her rooting for the green and gold – Go Pack Go!  Sara also loves to travel, and has visited 37 of our great 50 states plus the District of Columbia.

*Registrations are held through Commonwealth Financial Network®.

Kristin Kaminski

Operations Manager, Tomahawk Office

Kristin joined MainStreet Investment Group in September 2015 as our operations manager. She is responsible for coordinating new business, processing account transfers, administrative client inquiries, scheduling appointments, and any other activities that may arise in our office.

Before joining MainStreet Investment Group, she worked for Edward Jones as a branch office administrator. Kristin and her husband, Jerry, reside in Tomahawk. Between them they have seven children and are very active following the children's sports and activities. In Kristin’s free time, she enjoys golf, kayaking, and cross-country skiing.

Susan Garrison

Marketing/Client Relations, Tomahawk Office

Susan joined MainStreet Investment Group in 2005 as a client service associate. She is currently our marketing/client relations liaison and is responsible for the marketing duties in the office, including maintaining superior client service and assisting with day-to-day client service requests.

Susan graduated from the University of Wisconsin-Eau Claire in 1988 with a bachelor’s degree in business with an emphasis in marketing. Prior to joining MainStreet Investment Group LLC, she worked at Figi’s in its Marketing department and Tenneco Inc. as transportation administrator.

Susan resides in Tomahawk with her husband, Ron. They have two daughters that have graduated from college and have entered the "adult world".  Thankfully, both girls still like to come home on occasional weekends, especially if the weather cooperates for waterskiing or snowmobiling. In Susan's free time, she enjoys walking their black lab, boating, snowmobiling, cooking, and volunteering at church.

Lollie Plantenberg

Client Relations Assistant, Tomahawk Office

Lollie has always been a part of our team, but in 2015 she took on a permanent role in our office when she sold her own business - Medical Practice Solutions.  Lollie wears many hats in our office, including handling the bookkeeping and planning team activities for MainStreet Investment Group.  Lollie is a breath of fresh air as she has a wealth of knowledge in many areas, an infectious smile and laugh that are always present, and if anyone is ever in need of help, Lollie is the first to roll up her sleeves and jump in.

Maggie and Lucy

MainStreet Mascots, Tomahawk Office

Maggie joined MainStreet in 2013 with the addition of her little sister Lucy in 2014.  Randy and Lollie’s pets bring a lot of joy to our office with their tails wagging as they go from office to office to get their ears scratched and their occasional bursts of energy with their toys. The doggies delight in greeting our clients when they arrive with the opportunity for extra petting sessions.  Maggie and Lucy aren’t always in the office, but visit from time to time and enjoy their naps on Randy’s couch whenever they can.