Zenken boosts a lean sales team with ChatGPT Enterprise

Zenken boosts a lean sales team with ChatGPT Enterprise

Zenken is rethinking sales with AI—cutting preparation time, improving win rates, and shifting focus to higher-value work.

Zenken combines GPT‑5, custom GPTs, image generation, and the latest OpenAI models and tools to accelerate both of its core businesses: web marketing and the fast growing overseas human resources business. As one of the first companies in Japan to roll out ChatGPT Enterprise across the organization, Zenken is putting an AI first approach into practice and seeing clear business impact.

Today Zenken reports:

• More than 90% weekly active usage of ChatGPT Enterprise
• Average time savings of 30 to 50% across knowledge work tasks
• 5 to 15 additional hours per employee every month, reinvested in higher value work
• 50 million yen in annual outsourcing cost savings compared with the previous year

Before adopting ChatGPT Enterprise, Zenken relied on manual processes for a wide range of knowledge tasks. Employees spent large amounts of time on research, summarization, translation, and content creation. Sales teams also faced long preparation times for client meetings, which reduced the number and quality of customer conversations.

To address these issues, Zenken decided to introduce AI in a structured and secure way. Yuji Okada, Manager of the Corporate Planning Department in the Administration Division, explains that when they evaluated potential solutions, they “focused on twelve capabilities required for our business, such as security and advanced support for complex thinking,” and recalls that “ChatGPT Enterprise was the only solution to meet all of these conditions.” He notes, "Because we deal with client and sensitive internal information, preventing data leaks is non-negotiable. ChatGPT Enterprise guarantees that our data won't be used to train its AI. This security feature gave us the confidence to safely handle confidential data."

The availability of reasoning models was also a decisive reason for choosing ChatGPT Enterprise. In Zenken’s core web marketing business, teams need to analyze clients’ business challenges in depth and propose strategic solutions. The reasoning model released by OpenAI in 2024 provides the advanced support for complex thinking that Zenken was looking for and has further accelerated the company’s use of AI. Okada explains, “The reasoning model goes beyond simply providing information and supports management level decision making in areas such as market analysis, competitive strategy, and evaluation of new business opportunities.”

Today, the reasoning model improves the quality of strategy planning and analysis across teams and is also used to examine Zenken’s own management issues and new challenges from a strategic perspective. It has become a key driver of Zenken’s business growth.

The impact of ChatGPT Enterprise is especially visible in sales. Before using ChatGPT Enterprise, the sales team had to spend large amounts of time on preparation work such as researching prospects, creating proposal materials, and writing sales emails. Okada recalls, “Even before we could think about increasing the number of clients we approached, our people were already losing a lot of time on preparation. Because they had to respond to inquiries and create proposal documents, the time they could actually spend with customers was limited, and sometimes we missed out on opportunities.” Writing each email also took time, which created a natural limit on how many prospects a salesperson could reach in a single day.

By rolling out ChatGPT Enterprise across the company, Zenken has significantly improved the quality of its sales activities. The table below compares the sales process before and after ChatGPT at each phase.

| Phase | Before ChatGPT | With ChatGPT | | :--- | :--- | :--- | | Preparation phase | Gather information manually | Automated research and synthesis | | Discovery phase | One way, checklist style questioning | Deep analysis and strategic questioning | | Meeting phase | Answers often deferred to a later follow up | Real-time support and data retrieval | | Proposal phase | Standard product centric proposals | Strategic, personalized solutions |

As a result, Zenken has seen clear gains in sales performance:

• Proposals passing initial review up 15 to 20%
• Win rate for new deals up 5 to 10%
• Approval rate for final proposals up about 30%

“ChatGPT helps us shorten the time required for research and preparation, while also making our conversations with clients smoother,” explains Okada.

ChatGPT Enterprise has also become essential to Zenken’s fast growing overseas human resources business. Because most employees are native Japanese speakers, the company previously had to devote significant time and budget to translating job postings, contracts, and other documents for overseas candidates. Okada recalls, “When we needed to communicate in multiple languages including English, conventional translation tools often failed to carry over the right context and nuance, which made some international communication quite challenging.”

After implementing ChatGPT Enterprise, the team was able to accurately translate a wide range of documents into English and other languages. This allowed them to cut outsourcing costs while significantly increasing translation speed. “Even with a smaller team, we have been able to maintain an organization that continues to drive revenue growth,” says Okada.

Employees are also using ChatGPT in languages beyond English to gather information from news sites, technical articles, and other sources that are important for the business. This makes it easier to design new services and business initiatives with global expansion in mind and enables more people at Zenken to participate directly in cross border work than ever before.

ChatGPT Enterprise is reshaping how day to day work gets done at Zenken. Teams now use ChatGPT to generate first drafts of sales emails, proposals, marketing content, and internal documents in minutes, and overall productivity has roughly doubled across the organization. Work that was previously outsourced is increasingly handled in house, cutting annual outsourcing costs by around 50 million yen and improving margins. “Instead of being tied up in repetitive tasks, employees across the company now have more time to focus on the substance of their proposals,” says Okada.

Adoption is also strong at the individual level. Weekly active usage of ChatGPT Enterprise exceeds 90%, and employees send an average of about 900 messages per person each month. “It has become second nature for us to turn to ChatGPT first,” Okada explains. “We use ChatGPT to develop an initial hypothesis and then discuss it with our managers or colleagues. Working this way has greatly reduced the time people spend feeling stuck before they talk to others or move forward.”

For Zenken, ChatGPT Enterprise is more than a tool. In Okada’s words, it has become a partner that is changing how employees think and work. The company now sees ChatGPT Enterprise as a core platform that supports everything from day to day efficiency and strategic planning to talent development and, ultimately, company wide transformation.