A Locally Managed, 100% US Company

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Roland Certeza, President and Chief Executive Officer of GTA. Certeza has been instrumental in the company’s strategic initiatives innovating GTA for the past 13 years. As a results-proven leader, he has led the way to GTA’s globalized investments in the undersea cable industry, grown GTA’s retail footprint, transformed GTA’s portfolio and ignited a vision for the future of GTA.

As a telecom veteran, Certeza infuses a new dynamic culture to Guam’s telecom industry with his experience working with the world’s most renowned companies such as Apple, Verizon, Sprint and Deloitte & Touché. His extensive expertise in Sales & Marketing has ignited creativity and innovation in the telecom industry on the island.

Certeza holds a B.S. in Business Administration-Accounting from San Diego State University and is a proud Alumni of the University of Guam where he obtained his MBA. He is also an active member of the Island Sustainability Community Advisory Board created to shape and cultivate a sustainable future for our region.

While Certeza devotes his time to GTA and its growth, he enjoys his time with his wife Amy and his passion for surfing.  Certeza is the son of Gerry and Lina Certeza.

Joseph Shinohara joined GTA in 2007 and has served as Finance Director, Vice President of Finance/Controller, and Executive Vice President of Finance.  He was appointed Chief Financial Officer by GTA’s board of directors in July 2018.  In this senior leadership position,  Shinohara has a relentless focus on maximizing the efficiency of GTA’s investments and is responsible for GTA's day-to-day financial strategy and operations.  He was instrumental in two transitions of the company to new investors, new business initiatives and strategic investments, and a key contributor to an improved credit rating and debt financing.

Shinohara is an active CPA and CGMA license holder and a member of the American Institute of Certified Public Accountants and Guam Society of Certified Public Accountants.

Andrew Gayle is the Chief Operating Officer of GTA, Guam’s oldest telecommunications company, offering services to the island for over 60 years.  With more than 30 years of diversified experience in telecommunications and Information Technology (IT).

He joined GTA in 2005 after it had become privatized and held a succession of senior management roles in both sales and operations within the company.  Under his leadership, GTA expanded the business from being a basic telephone service provider to the first telecommunications company on Guam to offer full telecommunication services of phone, cellular, Internet, and digital TV service.  Gayle led several initiatives to include building and operating the cellular network and spearheading GTA’s smartphone strategy, including being the first on island to launch Blackberry in 2007 and iPhone in 2009, becoming the second US carrier to launch the iconic device after AT&T.  He also launched GTA’s digital TV in 2008.

Gayle was born and raised in Guam and continues to reside there with his wife and three children.  His local civic duties include chairmanship of the Guam Solid Waste Authority, member of the Rotary Club of Guam, and a long-time Mathcounts volunteer moderator.  He holds a degree in Computer, Electrical and Systems Engineering from Harvard University.  When not spending time with family and working,  Gayle loves to golf and is Handicap Chairman of the Nunu Golf Club.

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Jon Nathan “Nate” Denight joined GTA in August 2021, serving as Vice President of Marketing.  Denight brings a wealth of knowledge and professionalism with over 20 years of marketing experience, specializing in brand management, creative production, and event planning.  In his role, he oversees the marketing team, designing, implementing, and monitoring effective marketing strategies that align with the company’s business goals.  

Born and raised on Guam, Denight previously served as Vice President and then President and CEO of the Guam Visitors Bureau from 2011 to 2019 and was the co-author of the Tourism 2020 plan, transforming Guam into the world-class destination of choice.

He is the recipient of the 2017 Reina A. Leddy Guam Young Professionals of the Year award by the Guam Chamber of Commerce.

Denight earned a bachelor’s degree in commerce from Santa Clara University in California in June 1999.  In his spare time, he enjoys travel and sports, but his biggest passion is living in Guam with his wife Lana, daughter Luna and dog Cali.

Sharon Davis is recognized for her dynamic, results-driven leadership—an approach that has shaped GTA’s commitment to customer experience for nearly two decades. In May 2024, she assumed the role of Vice President of Community Engagement and External Affairs, focusing on impactful partnerships and outreach programs—GTA Gives—that strengthen Guam’s communities.

Before this, Sharon served as Vice President of Customer Experience, directing a team of sales and support “ROCKSTARS” known for delivering customer-focused solutions. She began her GTA journey in 2006 as an Account Manager in Enterprise Sales, then advanced to Director of Client Services and ultimately VP of Customer Experience. Leveraging her Lean Six Sigma Green Belt certification, she excels at streamlining processes and championing the customer at every level.

A graduate of the University of Nebraska - Omaha, Sharon is deeply committed to giving back to her community. She sits on the boards of Junior Achievement of Guam (as Vice Chair) and the Guam Memorial Hospital Board of Trustees (as Secretary), and mentors GTA’s Junior Achievement Guam Company of the Year flagship program that empowers high school students through entrepreneurship, career readiness, and financial literacy.

Vice President, Operations Carl Leon Guerrero brings 30 years of telecommunication experience to GTA. As Vice President of Operations, his role is to establish operational and capital improvement project direction and implement effective operations and cost-effective systems to meet the company's current and future needs.

Carl started as a Chief Engineer with former government-run Guam Telephone Authority. He has had many highlights in his career, such as the implementation to convert Guam to Feature Group D Equal Access, the inclusion into the North American Numbering Plan, installation of the fiber core and distribution networks throughout the island, along with the complete transformation of GTA's wireless network from analog to digital.

Carl received his Bachelor of Science in Electrical Engineering from the University of Portland and is a graduate of Father Duenas Memorial High School in Guam. He is also a Professional Electrical Engineer certified by the Guam Professional Engineer Architects and Land Surveyor (PEALS) Board.

Andy LaBrunda is the Vice President of IP and Video Headend. He joined GTA in 2005, where he started his career in the company as a project manager for the deployment of the wireless GSM network. During his tenure at GTA, he led several technical groups as the Vice President of IT, deploying an ArcGIS platform for network expansion and led postpaid billing system conversions. Today, he oversees the IP and Video Headend departments, leading a rapidly changing digital TV landscape and redefining the industry with a next generation IP infrastructure.

In 2015, he led over 250 employees in engineering and construction during the roll-out of faster internet speeds with Fiber to the Neighborhood, which resulted in installing 250 miles of Fiber and the deployment of 350 neighborhoods. Prior to GTA he worked as a professor at the University of Guam teaching Computer Science.

Andy has also participated in the Silicon Village group as a presenter in the Guam Hacktober Festival, discussing practical applications of the Raspberry Pi. LaBrunda is a Simon Sanchez graduate. He is a board member of Code Foundation, a non-profit company whose goal is to enhance technical talent and develop technical resources for Guam residents and businesses. In his downtime he enjoys kitesurfing and snorkeling.

Jason Katigbak joined GTA in November 2024, serving as Vice President of Finance. He has over 20 years of combined assurance, accounting, project management, IT, and finance experience. Prior to joining GTA, he held senior financial leadership positions including Director of Business Optimization, Chief Financial Officer and Chief Accounting Officer at IP&E Holdings, LLC and Citadel Pacific. Jason also served as a Senior Manager at Ernst & Young, where he led audit teams specializing in various industries such as telecommunications, oil and gas, and governmental auditing, contributing to the enhancement of the firm’s audit quality and training programs.

In addition to his professional roles, Jason is an Adjunct Instructor at the University of Guam and Chaminade University, teaching accounting courses at both undergraduate and graduate levels.

He holds a Doctoral Degree from Bellevue University, an MBA from Delta State University, and an undergraduate degree in accounting and commerce from Colegio de San Juan de Letran - Calamba. Jason is a Certified Public Accountant (CPA), Certified Internal Auditor (CIA), Certified Fraud Examiner (CFE), and Chartered Global Management Accountant (CGMA). He has served as a past president of the Guam Society of Certified Public Accountants, the Association of Government Accountants Guam Chapter, and as a board member and Treasurer for Junior Achievement of Guam.