top of page

regional Leadership Team


Gary & Nikki Ubaldini

Regional Operating Principles

Gary and Nikki have been in real estate since 1986. They joined Keller Williams in 1998
intrigued by the leadership, culture, and opportunity potential.

The 7th level Gary and Nikki Real Estate Team have now successfully served over 5,000 families with over $800 million sold in real estate since 1986. Gary and Nikki also own 3 Keller Williams Realty offices with over 1,000 associates, 3 title companies, and are the Operating Partners for the Keller Williams South Florida Region with 35 Market Centers and over 6,800 associates. They are also partners in the Keller Williams Ohio Valley Region.

In addition, Gary and Nikki have extensive experience teaching as certified instructors for Keller Williams University. They continually sharpen their own skills through training and education for themselves. As vast believers in professional growth and opportunity, they are excited, motivated, and determined to add value to other people’s lives and businesses!

Email Gary and Nikki: and


Thamara Perez

Executive Assitant to

Regional Owners

Thamara began her career with Keller Williams in 2013. She had bought and sold real estate with Keller Williams agents previously and had always been impressed with their professionalism, knowledge, and culture.

Thamara began as a Director of First Impressions (front desk), quickly moved into the role of Director of Agent Services, and eventually was the Regional Operations Manager for the Keller Williams South Florida Region. She currently holds her Real Estate License and is the Executive Assistant for Nikki Ubaldini, successfully juggling the everyday demands of the Ubaldini entities.

Email Thamara:


Mark Olesh

Regional Director

Mark’s journey began as a Keller Williams agent in 2001.   He capped in his first year and became an ALC member. He took the Team Leader Opportunity in 2003 and led the Clearwater Market Center to more than double the number of agents – a high of 210. Under his leadership, the total profit in the market center grew by 4 times to nearly $400,000. Mark enjoyed coaching many of the top agents in the market center as well.

Named South Florida Regional  Director in January of 2007, the area now has 31 Keller Williams offices from Melbourne to Miami. The number of agents has more than doubled to 6,000, do over 30,000 closed units a year, and Closed Sales have tripled to over $8.5 billion annually.

Mark spent 15 years in local television and loves to teach. An Emmy nominated television news and sports anchor, Mark interviewed politicos Margaret Thatcher, George W. Bush, Jack Kemp, and Gerald Ford.  He also covered top sporting events including the Super Bowl, Rose Bowl, and the Daytona 500.


Email Mark Olesh:

Jon Photo 2 0923.jpeg

Jon Sterling

Area Director

Jon began his real estate career in 2002. He started his own brokerage in Chicago and eventually merged it with Keller Williams, where he built and led teams in various locations across the US. Jon moved to London in 2014 to launch Keller Williams in the UK, which gave him an introduction to international real estate. The London experience planted the seeds for Jon to launch an international property portal that currently covers 42 countries around the world. 


The part of his job he enjoys the most is teaching and coaching real estate agents. Jon has been the personal business coach to some of the top agents in the US and Europe, which gives him a unique perspective when it comes to building big real estate businesses. Jon has lived on three continents and currently resides on the East Coast of Florida with his family. 

Email Jon Sterling:


Alex Nobiling

Regional Operations Manager

Alex moved to the Tampa Bay area from Chadron, Nebraska in August of 2022 after receiving her Master’s Degree in Organizational Management! She joined Keller Williams as Regional Operations Manager of South Florida shortly after, using her organization and customer service skills she gained by previously working at a state college as Human Resources Coordinator. She joined Keller Williams because she was interested in the team-oriented style of leadership, and the success of the region!

Email Alex:

Zena Martin.jpg

Zena Martin

Regional Market Center Administrator

Email Zena:

Ryan Yarbrough Pic.png

Ryan Yarbrough

Regional Technology Director

Ryan was born and raised in the Tampa Bay area by a family of Realtors and wanted a change of scenery. He went to Florida State and worked on a computer science degree. After college Ryan learned Real Estate was in his blood and joined his family in the business. After a market collapse, Ryan moved to Knoxville, Tennessee, and opened up a brokerage with some friends. Ryan learned how difficult being a business owner is and the different challenges that come with owning your own brokerage. One of the biggest obstacles Ryan worked hard to overcome was training agents. Right away he used his technology background to leverage the tools he had to run a more efficient business that could train and operate with less friction.

Ryan then moved back to Florida and Join Keller Williams and worked towards building his team and leveraging the tools and technology KW had to offer. He spent the next 6 years as a member of the ALC as the technology chair and built a strong presence in the Clearwater Market Center. 

Email Ryan Yarbrough:

bottom of page