Customer experience as the driving force behind a growing company

International Tax Review is part of Legal Benchmarking Limited, 1-2 Paris Garden, London, SE1 8ND

Copyright © Legal Benchmarking Limited and its affiliated companies 2026

Accessibility | Terms of Use | Privacy Policy | Modern Slavery Statement


Customer experience as the driving force behind a growing company

Sponsored by

26Copper Wolf Mexico.png

Through a specialized business model, a national vision and a firm commitment to talent, Copper Wolf has built a value proposition focused on understanding the specific challenges of each client and supporting their growth in increasingly complex environments.

Originally from Torreón and trained as an accountant, Mario Castillo spent much of his professional career at renowned consulting firms. However, after years of experience working with companies of varying sizes and across diverse sectors, he identified an opportunity: to create a firm where specialization, partner participation, and service quality were as important as technical expertise.

With that vision, he founded Copper Wolf in 2017 along with Víctor Bretado, Eduardo Ramírez, Bruno Fregoso, and Mario Nuño. What began as a firm specializing in tax matters has become a comprehensive consulting firm with a presence in various regions of Mexico and the United States. Their work has been recognized by International Tax Review, one of the most prestigious international publications in the sector.

Unlike many traditional consulting models, Copper Wolf adopted a multi-regional structure from the outset. For Castillo, understanding how each region operates, how decisions are made, and the particular challenges of each market represents a competitive advantage that is difficult to replicate from a single office or through standardized approaches.

“Over the years, we’ve learned that there isn’t just one way to do business in Mexico. Beyond technical knowledge, consulting requires understanding how organizations make decisions, how trust is built, and the unique dynamics of each market. Our regional presence allows us to understand these differences and provide much closer and more effective support to our clients,” says Castillo.

Currently, Copper Wolf has offices in Mexico City, Guadalajara, Monterrey, Querétaro and Torreón, as well as a presence in San Diego, California, which strengthens its ability to provide support to companies with both national and cross-border operations.

As its clients grew, expanded into new regions, or faced more complex regulatory environments, Copper Wolf identified the need to provide support beyond tax advisory services. Many of the new service lines arose directly from conversations with clients seeking to address increasingly interconnected challenges through a comprehensive advisory platform.

However, for Castillo, growth has never meant sacrificing the essence of the organization.

“Our clients aren’t just looking for technical answers. They need advisors who understand their business context, the risks they face, and the goals they’re trying to achieve. Staying a specialized firm allows us to be much more involved in those conversations and build long-term relationships,” he says.

This philosophy is reflected both in customer service and in the way the organization develops its talent. In an environment where competition for skilled professionals continues to grow, Copper Wolf has invested in training, mentoring, and leadership programs designed to promote the professional growth of its employees and strengthen the firm's long-term sustainability.

As it approaches its tenth anniversary, and in an environment where organizations face increasingly complex fiscal, regulatory, and operational challenges, Copper Wolf is committed to a model that prioritizes a deep understanding of each client's business. For the firm, close client relationships are not just a service feature, but a tool for generating better decisions and long-term partnerships.

The information provided in this article is for general informational and educational purposes only. It is not intended as financial advice. Professional advice should not be relied upon. Readers should not rely solely on the content of this article and are advised to seek professional advice tailored to their specific circumstances. We disclaim all liability for any loss or damage arising directly or indirectly from the use of or reliance on the information presented.

more across site & shared bottom lb ros

More from across our site

The ambitious big four challenger firm has also appointed ex-RSM partner Brad Ashton to build out its customs and global trade practice
The big four firm allegedly reviewed backdated documents and signed off on accounts that removed hundreds of millions of dollars of Abramovich’s assets
New Tier 1 entrants and an expanding cohort of established players indicate that law firms are becoming increasingly credible challengers in Europe's TP market
Awards
Leading firms and individuals gathered in Dubai to celebrate standout legal, dealmaking and tax work across the region
Tax authorities want more revenue, have better tools to find it and are increasingly willing to fight for it
Audifina, the sixth-largest firm of its kind in Lithuania, will bring a 90-strong team with offices in Vilnius and Kaunas to RSM’s international platform
As global capability centres use AI to deliver services, MNEs face a fresh wave of PE and TP exposure that their existing playbooks weren't built for
The deal for Comtax hands Ryan immediate scale in Brazil, with a near-70-strong team serving clients from São Paulo
The arrivals of Julio Castro and Adam Blakemore mean the firm has added six tax partners to its global practice since the start of 2025
Tax authorities have gained unprecedented transparency through CbCR, but a new study suggests they may not be looking in the right places
Gift this article