Meet the Leadership Team
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.
Crena Byerly is an empowered female leader in technology, an expert in enterprise sales, and notably one of the few undersea cable subject matter experts in our region.
Working her way up the ranks from an Account Manager in 2005, Crena has been promoted to VP of Enterprise Sales. In her new role, she will lead GTA’s enterprise sales team as they continue to provide the best, most reliable services that power our island’s businesses, as well as position Guam as global telecommunications hub through strategic partnerships.
Sharon Davis is a fun, energetic, and passionate leader propelled to take GTA to new heights to provide the best customer experience on Guam.
As Vice President of Customer Experience, she leads a strong team of over one-hundred service professionals and everyday problem solvers to ensure customers feel happier, stay loyal, and truly feel connected with GTA. Her GTA journey started in 2006 in business sales, and held various leadership roles in the company. Today in her latest role as VP of Customer Experience, her goal is simple - It’s to make customers happy!
She coined the term ROCKSTARS to refer to her customer-focused teams in the 24/7 customer support and technical assistance centers, our SMART handset technicians, those in our service central-dispatch scheduling, along with the customer care-retention, retail sales and operations, and business support teams. Sharon cares for customers (It is in her DNA!) and is known to occasionally answer calls at the GTA call center at any time of the day alongside her dedicated teams. She is inspired to create an impact in the customer journey by creating an experience that is seamless, easy, and extremely personable.
She is a graduate of the University of Nebraska (Omaha) with a Bachelor of Arts in Communications, received a Certificate of Management from the University of Guam, is currently Apple iOS Service Certified, and completed Dale Carnegie Leadership and Berkeley High Impact Leadership training programs. Sharon empowers Guam’s youth as a board member of Junior Achievement of Guam. She is a dedicated public servant, sitting as a member of the Board of Trustees at the Guam Memorial Hospital. During her free time, she enjoys paddle boarding, listening to podcasts, working in the yard, and spending time with her grandkids.
Stacy Cunliffe Elarmo
Stacy joined GTA in 2019 and is now the Vice President of People Operations. She is a proven strategic People Operations executive with well over 15 years of experience in various technology industries. Stacy has deep experience in the Human Resources and Finance fields. She is responsible for the People Operations Infrastructure and continues to foster a healthy and productive culture at GTA. She’s revolutionized GTA’s HR function to one that is people centered, resilient, and a critical strategic partner in achieving the organization’s business goals.
Prior to returning to Guam, Stacy led and consulted teams in organizations such as Biosite Inc., Tandem Diabetes Care, Ivera Medical, and Artefact Group. She is a disrupter and a champion of change who is focused on creating purpose, care, and connection at work. She drives a holistic approach to the employee experience and workforce development, which has resulted in being awarded by Seattle Business Magazine ‘100 Best Places To Work’ in 2014, 2016, 2017 and ‘Guam’s Pika’s Best Place To Work’ in 2020, 2021, and 2022.
Stacy is an alumna of St. John’s School. She holds a bachelor’s degree in Psychology and a Minor in Japanese from the University of San Francisco. Additionally, she earned her Certificate in Human Resource Management from Cornell University in 2014. She also serves as one of GTA’s Junior Achievement Advisors and is a member of the Guam Department of Labor’s Workforce Development Board.
Jon Nathan Denight
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.
David Chase joined GTA in 2007. He brings over 30 years of experience in the telecommunications industry, with a deep technical background in product definition, development, applications, and deployment with emphasis in telecommunications, wireless systems, control systems, and signal processing fields.
Prior to his employment with GTA, Chase held the position of President and CEO of Vareda Engineering, Inc., based in California, as well as prior positions at Agile Materials and Technologies, Inc., and Superconductor Technologies, Inc. also in California. Chase has 12 issued patents, several pending applications, and 7 publications on a variety of technical advancements, in the signal processing, RF modeling, Magnetic Resonance, and RF system design fields.
Chase graduated from the University of California, Santa Barbara with a Master of Science in Electrical Engineering (MSEE), specializing in Signal Processing, and is a Member of the Institute of Electrical and Electronics Engineers (IEEE).
Gene Crisostomo is the Vice President of Network Operations at GTA, where he has worked for over 25 years, starting as a laborer and working his way up.
He has led several major projects, including the migration to IP-based softswitch, the upgrade of the wireless core to virtualized machine platforms, and the implementation of 4G LTE and 5G wireless radio area networks. Gene manages a team of 50 who oversee the Wireless Core and RAN, Voice Switching Core, Optical Transport, Network Operations Center, IP Routing and Switching, and Business Service Solutions team.
His technical expertise and leadership skills have been instrumental in enhancing the company's overall network performance and contributing to its continued success.
Daniel J. Tydingco
Before joining GTA, Dan Tydingco served as the Director of Policy, Planning and Community Relations for the United Courts of Guam. Prior to that, he served as Executive Officer of the Supreme Court of Guam. Tydingco began his public service career in 1983 as a congressional aide in the U.S. House of Representative for then Guam Congressman A. B. Won Pat. He later served as the Deputy Press Secretary for the late Governor Ricardo J. Bordallo and as Chief-of-Staff for the legislative committees on Water, Utilities and Telecommunications as well as Judiciary and Criminal Justice.
Tydingco holds a bachelor's degree in Political Science and History from Regis University in Denver, Colorado. He is a member of the boards of directors of various professional, civic and service organizations including recent service as Chairman of the Port Authority of Guam Board of Directors and the Board of Catholic Cemeteries for the Archdiocese of Agana. He also chaired the 2010 gubernatorial Transition Team for Governor Eddie Calvo and Lt. Governor Ray Tenorio, and chaired the Economic Development Committee for the 2018 gubernatorial transition team of Governor Lou Leon Guerrero and Lt. Governor Joshua Tenorio.
Strategic Infrastructure Development
Carl Leon Guerrero
Strategic Infrastructure Development
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.
Yudishter Parmar joined GTA in 2006 as a Managing Director of Finance. In his current role as the Vice President of Business Planning and Process Control, he is instrumental in day-to-day collaboration on the company's financial-related activities, providing both operational and project support to the business.
Yudishter is responsible for managing recurring processes related to budget management, cost-benefit, capital projects, and business case analysis, along with quarterly forecasting. He oversees teams responsible for internal audits, revenue assurance, regulatory filing, and collections. Before his work at GTA, he worked as the Construction Project Manager at DFS Guam LLP and held a position as a financial consultant with Deloitte and Touche LLP.
Yudishter holds a Bachelor of Science in Computer Science from the College of William and Mary. He continued his education at Tulane University, earning a Master of Business Administration in Corporate Finance and International Management.