Leadership Bios

Gerard Zimmerebner


Mr. Zimmerebner, C.P.A., has been with Sigma Solutions since 2001 and is a Certified Public Accountant with more than 25 years experience. Mr. Zimmerebner has been in a Controller capacity for several South Texas enterprises, in charge of accounting, treasury, human resources, and cash management functions since graduating from college. Mr. Zimmerebner graduated Summa Cum Laude from St. Mary’s University in 1981.

Sales Team Leadership Bios

Joe Barrett

Executive Vice President, Sales

Mr. Barrett manages the day-to-day sales operations for Sigma. Under his leadership, the team of account executives has grown significantly in size and revenue generated. He attributes that success to recruiting top talent and providing his team with the resources necessary to succeed and grow. Before joining Sigma, Mr. Barrett was a Regional Sales Manager with Sun Microsystems. Prior to that, he served as Vice President of Sales and Marketing for Unigen Corp. He earned his Bachelor of Science in Consumer Economics from Texas Tech University.

Lanett Blum

Ms. Blum is the Regional Vice President of Sales for the Dallas Region.  She is responsible for the sales and operations for Dallas/Ft. Worth, West Texas and East Texas. Ms. Blum leads a team of Account Executives who partner with customers to help them achieve their desired business outcomes.

She has worked in IT for over 20 years in various capacities selling hardware and software, designing partner programs, and selling services including managed services, cloud and collaboration solutions. Ms. Blum has held sales leadership roles for Sun Microsystems, Oracle Corporation and Pivot Technology Solutions.

Ms. Blum has a Bachelor of Science degree in Business Administration with a minor in Economics from the University of Nebraska – Lincoln. At UNL, she studied abroad for a summer at Oxford University.  She also earned a Master’s Degree in Business Administration from Denver University.

Steve Hartofelis

Regional Vice President of Sales for Central Texas

As regional vice president, Mr. Hartofelis is responsible for managing sales and operations in Austin and San Antonio.  In addition, he will be responsible for managing the Sigma partnership with Rackspace globally. Mr. Hartofelis has spent over 23 years on the OEM side of the business serving in a variety of roles from Account Executive to Sales Manager.

Most recently, he served as the Dell|EMC District Sales Manager responsible for the global health and growth of Rackspace.  Before joining Sigma, he was with Sun Microsystems where he consistently outperformed the company’s goals and objectives.  Prior to Sun Microsystems, he spent time at both Compaq/DEC & Cabletron.  Mr. Hartofelis graduated with a Bachelor of Arts in International Business with a minor in Accounting from New England College.

Rob Jezek

Regional Vice President, Sales – Oklahoma

Mr. Jezek is a native Oklahoman who has been in information technology for more than 20 years. His passion for helping customers with their IT investments comes from his commitment to the community where he lives and works. That passion has been instilled in his team, along with the promise to be a customer’s advocate and stand behind the solutions they sell.