Leadership Bios

Scott Gruendler

Pivot Chief Services Officer

Mr. Gruendler is Chief Services Officer for Pivot Technology Solutions where he oversees the strategy and delivery of services which are offered across the Pivot portfolio of companies. This Integrated Service Operations team delivers consistent high quality, high-value outcomes for customers based on industry-leading methodologies.

He has been in the IT field since the late 1980s, working for a number of value-added resellers and combining business acumen with deep IT experience. Mr. Gruendler has built the combined services and IT product strategy that differentiates Sigma from its competition and has been instrumental in the company’s significant year-over-year growth.

Additionally, Mr. Gruendler led Sigma Solutions through an important growth phase, including several acquisitions that broaden the scope of the company’s offerings while retaining its close focus on data center infrastructure.

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

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.

Rob Jezek

Regional Director, 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.

Tom Prentice

Regional Director, Sales – Austin/San Antonio

Mr. Prentice joined Sigma in 2008. Mr. Prentice is responsible for developing and maintaining strategic vendor partnerships in the Austin and San Antonio region, managing the sales team, maintaining customer relationships and driving revenue. Mr. Prentice has worked in the IT industry for the last 20 years, and most recently was the Area Director at a VAR/Reseller where he spent nine years.

Mark Waldheim

Regional Director, Sales – Houston/New Orleans

Mr. Waldheim oversees the business operation of Sigma’s Houston and New Orleans offices focused on our customers’ success across all industries.  He brings over 25 years of sales and sales leadership experience having worked for leading technology manufacturers such as EMC and NetApp. He also spent several years at Gartner as Regional Vice President for the Southeast US and Latin America.  Mr. Waldheim earned a Bachelor of Business Administration degree from the University of Texas at Austin.