Diana Rosales – Sumitomo Corporation of Americas 

Energized to cut deals in an industry 

It’s a relatively new and obscure acronym, CCUS, as in carbon capture, utilization and storage, and there’s a lot of it either underway or planned in the oil-rich Canadian province of Alberta. The demand for it should only soar, which is what with carbon reuse standing to diversify the energy sector, develop clean hydrogen, and bring the world closer to a net-zero electricity grid. 

Diana Rosales | Legal Director M&A |  Sumitomo Corporation of Americas 

Diana Rosales | Legal Director M&A |  Sumitomo Corporation of Americas

Alberta is issuing CCUS rights through a competitive process that enables the development of storage hubs in areas such as rock formations—something the province has in spades—and it’s garnering no shortage of interest. Among the most exciting projects pending in the central prairie is the Canadian subsidiary of Japan-based Sumitomo Corporation, partnering with a Canadian company to develop the RETI East Calgary Region Carbon Transportation & Sequestration Hub project with the potential to store up to 10 million tonnes of carbon dioxide annually.  

In May, the ink dried on a joint development agreement between Sumitomo and Calgary-headquartered Reconciliation Energy Transition Inc.—RETI—with much credit due to young Diana Rosales. The Mexican-born and New York City-dwelling legal director of Sumitomo’s mergers and acquisitions, she helped get the process going last year and speaks excitedly about the partnership’s potential. 

“It will help us achieve the sustainability goal and ESG objectives (environmental-social-governance) that we have in investing in clean energy by having more sustainable projects to benefit the environment,” she tells Vanguard from New York City just after sealing the deal. 

Rosales did her part by assuming leadership during the complex negotiations, identifying which risks Sumitomo could assume, creating legal protections for her employer, and working with taxing and legal advisors to ensure regulatory compliance. Sumitomo and RETI, she explains, are in it for the long haul, and the project is scheduled to achieve its first operations in 2026.     

Industry smarts 

That’ll give Rosales plenty of time to further familiarize herself with another industry in another country. She’s been doing that since joining Sumitomo in March 2020 after serving the company as an associate from the New York office of Morrison & Foerster. Sumitomo is one of the world’s leading traders of goods and services; its core businesses include energy, automotive, social infrastructure, agriculture, life science, mining, and energy innovation. Rosales, being business-minded and multilingual, has enabled key deals while proving to be a fast learner. 

Diana Rosales | Legal Director M&A |  Sumitomo Corporation of Americas 

Asked about her highlights, she mentions overseeing the legal work and contracting that factored in Sumitomo winning the bid in 2021 to provide rails for the Mayan Train, which began operations this past December. It’s the biggest infrastructural project to date in Mexico’s Yucatan Peninsula, covering 1,500 kilometers and, beginning at Cancun International Airport, connects Caribbean tourist destinations with lesser-known sites inland, including historic Mayan ruins. 

Rosales having an eye for fine print, she pored over the guidelines, concluded the project was well within Sumitomo’s capabilities, and finalized arrangements with subcontractors. Fluent in English and Spanish, she proved quite the bridge-builder between Sumitomo’s Tokyo team and Mexican authorities. 

“I’m super detail-oriented and want the transaction to happen,” she says. “Whatever the issue, my goal is to overcome problems, do due diligence and close the deal. Part of my role is understanding the risk and taking what we can assume.” 

At home in-house 

Having counseled Sumitomo on its projects in Latin America as a private lawyer, Rosales says the transition to in-house law seemed a logical progression of her career path. But she’s quick to credit her former colleagues at Morrison & Foerster for bringing out the best in her. One partner even encouraged Rosales to pursue a position at Sumitomo, and once the company realized what she had to offer, the role expanded. 

Diana Rosales | Legal Director M&A |  Sumitomo Corporation of Americas 

That said, Rosales says nothing came easy, there being cultural and societal barriers to overcome while essentially brokering international deals. She found that Japanese culture is conservative and based in trust, making it a challenge to gain buy-in from the decision-makers. Here again, Rosales’ worldliness and multilingualism put her on equal footing. 

“They appreciated that I can communicate with their Spanish-speaking counterparts and resolve issues,” she says. “Once I got their trust, they really appreciated my work and saw me as an ally.”  

She’s doing her part to chip away at the proverbial glass ceiling, speaking with management about how empowering women is socially responsible and good business to boot. Before too long, Rosales could be better positioned to do so. She aspires to lead a legal department and sees her prominent role as a positive sign. 

“I add a lot of value,” she says. “I have been the link to generating legal culture with Latin America and creating dialogue and trust. I have the skill set to be in a leadership position and integrate the company’s regions from a legal point of view because I speak the language.” 

Ambition learned early 

Rosales has always been ambitious; she was one of two daughters of an engineer father and a chemist mother and was further inspired by an attorney aunt who worked for Mexico’s National Supreme Court of Justice. She earned her law degree and post-graduate credentials in infotech and communications law at the Autonomous Technological Institute of Mexico in 2011 and 2012, respectively, and, after five years with Mexico City’s biggest law firm—Creel, Garcia-Cuellar, Aiza y Enriquez—enrolled at Georgetown University for a masters program in international business and economic law. 

Diana Rosales | Legal Director M&A |  Sumitomo Corporation of Americas 

Those couple years in Washington, D.C., proved eventful, Rosales’ horizons broadened by living in the city where U.S. laws are made and being invited to a meet-and-greet with Supreme Court Associate Justice Sonia Sotomayor who, being of Hispanic descent, wanted to meet young Latina students. Later, to Rosales’ delight, she learned that her new husband was a distant relative to Sotomayor’s late colleague on the court, Ruth Bader Ginsburg. Though her husband had never met Ginsburg, she still agreed to meet with the young couple. 

“She was super inspiring,” Rosales says. “A remarkable woman who inspired me to be all I can.” 

Rosales seems to be doing just that and has realized at least one of her goals: practicing transactional law in New York City. Life’s good for Rosales and her husband, “a true New Yorker” who owns his own tech firm. The couple lives in Midtown Manhattan and has a soon-to-be 2-year-old son. 

The Big Apple’s far from Mexico City, but Rosales says she loves it. She exercises and enjoys concerts when time permits, but with work and a toddler, time doesn’t permit much recreation.  

But Rosales has strived for this, and she strives for more, given that Sumitomo is pursuing alternative and renewable energies as its next growth sector. 

“It’s been a learning process with us engaged in so many different industries,” she says. “It’s been very challenging but so exciting and interesting. I love putting together the framework for these deals.” 

Published on: July 2, 2024



Showcase your feature on your website with a custom “As Featured in Vanguard” badge that links directly to your article!

Copy and paste this script into your page coding (ideally right before the closing tag) where you want to display our review banner.


I was honored to be the subject of an article. I enjoy reading Vanguard articles and seeing how other attorneys got to their positions and see their jobs. It's also interesting to see how different law firms partner with the subjects of the articles.
– Henry Marquard, in-house counsel, Stanley Consultants Inc.
It was a great honor to be featured in Vanguard Law. Working with every member of the team, from the initial interview with Erin Clark, through production with Victor Martins, writing the article with Taryn Plumb and creating the final content with Dave Gushee, was a true pleasure. Everyone was very professional, enthusiastic and supportive, and their creative approach and positive attitude clearly came through in the final product.
– Kevin C. Rakowski, Senior Vice President, Deputy General Counsel, Compliance with Radian Group Inc.
The piece highlighting my company, Bob Baker Enterprises, Inc., came out fabulous. Our company is in the new and used car sales and service industry. Everyone was great to work with and extremely professional. They produced a high-quality product and have provided expert assistance and guidance post-production of the article.
– Wade Poulson, General Counsel, Bob Baker Enterprises Inc.
As promised in advance, my feature in Vanguard has increased my visibility within the profession and prompted more than a few people I have not communicated with recently to reconnect. One of the Italian law firms I have used in the past is now in the process of interviewing me for an article on their website and tweeting out the feature story. Activity and the number of people connecting with me on LinkedIn has soared, which is great. The Vanguard writers and editorial staff were great to work with—highly professional and made the effort to make the experience both fun and rewarding (they were also respectful of the time pressures and demands all lawyers face). I was very pleased with the experience and the final outcome. Needless to say, I have been very pleased. All in all working with Vanguard has been a very positive experience which generated good publicity for both Shawcor and myself. My sincere thanks.
– Tim Hutzul, General Counsel, ShawCor Ltd.


Summer I 2024



  • * We’ll never share your email or info with anyone.
  • This field is for validation purposes and should be left unchanged.