Safest AI Tool for Your Data: ChatGPT vs Claude vs Copilot

Updated June 22, 2026

The Hidden Data Risk AI Users Overlook

Last month, a junior analyst at a mid-size firm typed a routine question into Microsoft Copilot: "Summarize our Q1 revenue projections." Copilot obliged — pulling from a confidential board presentation the analyst was never meant to see. The file permissions in SharePoint said "available," so Copilot served it up without hesitation.

This isn't a hypothetical. Concentric AI documented that in January–February 2026, junior analysts at multiple organizations accessed confidential drafts through Copilot that should have been permission-protected. The tool worked exactly as designed — the permissions were the problem. ChatGPT and Claude work like handing someone a document — you decide what they see. Copilot is different. It gets a master key to your filing cabinet. The risk isn't misuse. It's that half your drawers were never locked.

The uncomfortable math backs this up. Most organizations obsess over whether OpenAI or Anthropic might train on their prompts. That's a legitimate concern. But sensitive data now makes up 34.8% of employee ChatGPT inputs, up from 11% in 2023, according to Cisco's 2024 AI Privacy Readiness Index and separately per Kiteworks' 2024 Sensitive Content Communications Privacy & Compliance Report. Meanwhile, Copilot sits inside your Microsoft 365 (M365) tenant with access to every file your employees can technically reach — and in most organizations, that's far more than anyone intended.

Data leaks from generative AI are now the #1 security concern at 34% of organizations, up from 22% the prior year (secureprivacy.ai).

The privacy conversation has been dominated by training opt-outs and data retention windows. Those matter. But the statistically larger breach surface is the one organizations already deployed and forgot to lock down: their own file permissions, now amplified by an AI that can search, summarize, and surface anything it can see.

Key Takeaways

• Training opt-outs vary wildly by plan. Free and consumer tiers of ChatGPT and Claude train on your data by default; business plans and APIs do not. The plan you're on matters more than the vendor you pick.
• Copilot's biggest risk isn't Microsoft — it's your own permissions. The average organization exposes 3 million sensitive records through over-permissioned access (Concentric AI), and Copilot makes all of it instantly searchable.
• Certifications aren't security. OpenAI holds the broadest compliance portfolio, Microsoft inherits M365's framework, and Anthropic is narrower — but none of that protects you if your configuration is wrong.
• The API-vs-chat distinction is the most overlooked privacy gap. Every vendor's API offers stronger privacy than their consumer chat product.

Training Data Policies: Who Actually Uses Your Prompts?

The question everyone asks first — "Does this AI train on my data?" — has a more complicated answer than any vendor's marketing page suggests. It depends entirely on which plan you're on and which settings you've configured.

OpenAI (ChatGPT): On the free tier and ChatGPT Plus ($20/month), your conversations are used to train future models by default. You can opt out in Settings → Data Controls → "Improve the model for everyone," but most users never touch this. ChatGPT Team ($25/user/month, billed annually; $30/user/month monthly) and Enterprise (~$45–75/user/month) do not train on your data, per OpenAI's enterprise privacy commitments. The API offers zero data retention — your prompts aren't stored at all. OpenAI also provides Enterprise Key Management (EKM), giving customers control over their own encryption keys.

Anthropic (Claude): If you opt out, your data is retained for 30 days then deleted. If you stay opted in, data may be kept in disidentified form for up to 5 years, per Anthropic's privacy center. The critical distinction: Team, Enterprise, API, and Government plans never train on your data — privacy is the default for every business tier.

Microsoft (Copilot for M365): Copilot processes data entirely within your M365 compliance boundary and does not train foundation models on tenant data. On paper, this sounds ideal. Your prompts stay in your tenant. But "not training on data" and "keeping data safe" are different promises — and the second one depends on your organization's access controls, not Microsoft's policies.

The real takeaway isn't about which vendor is "safest." A developer pasting proprietary source code into ChatGPT Plus without toggling the training opt-out is feeding that code into OpenAI's training pipeline. The same developer using the ChatGPT API has zero data retention — the code vanishes after the response. Same company, same vendor, radically different privacy outcomes based on which product they opened in their browser. Every vendor's API offers stronger privacy than their consumer chat product. If your team handles sensitive data, the API (or a business-tier plan) isn't optional — it's the minimum.

Microsoft Copilot's Permission Problem: 3 Million Exposed Records and Counting

Copilot for M365 respects existing Access Control Lists (ACLs) — the permission rules your IT team set in SharePoint, OneDrive, and Teams. Microsoft Purview Information Protection encryption is also honored, enforcing usage rights on sensitive documents. On paper, this is solid architecture.

In practice, it's a liability. Most organizations have years of accumulated permission drift — files shared too broadly during a quick collaboration, folders left open after a project ended, SharePoint sites with "everyone except external users" access. Before Copilot, this was a theoretical risk. An employee would need to know the file existed and navigate to it. Copilot removes that friction entirely: ask a question, and it searches everything you're technically allowed to see.

Concentric AI's analysis found that the average organization exposes 3 million sensitive records through over-permissioned access. That's not a breach — it's the default state of most M365 environments, now made searchable by AI.

The security track record has concrete incidents beyond permission issues. CVE-2024-38206 (NVD, NIST, a Server-Side Request Forgery (SSRF) vulnerability in Copilot Studio, allowed attackers to leak internal Microsoft infrastructure information. And in the January–February 2026 incident, junior analysts accessed confidential draft documents through Copilot queries — documents that were technically available to them due to broad permissions but were never intended for their eyes.

At $30/user/month on top of an M365 license (minimum ~$42.50/user/month total with M365 Business Standard, per Microsoft's pricing), Copilot is the most expensive option — yet organizations may be paying a premium to amplify their own permission problems.

What separates this from ChatGPT or Claude's privacy risks is the direction of exposure. With those tools, you control what data enters the system. You paste text, upload a file, type a question. The risk surface is what you choose to share. With Copilot, the risk surface is everything your M365 tenant contains — and the AI actively searches it. You're not just trusting Microsoft with your prompts; you're trusting that every SharePoint permission, every OneDrive sharing setting, and every Teams channel membership in your organization is correctly configured.

For organizations with mature information governance — active access reviews, Microsoft Purview labels consistently applied, principle-of-least-privilege enforced — Copilot can be genuinely safe. For the majority that haven't audited permissions in years, deploying Copilot at $30/user/month is paying to make your existing security debt visible and exploitable.

How to Secure Your Data: Encryption, Access Controls, and Pricing Tradeoffs

Securing your AI tools isn't about picking the "safest" vendor — it's about configuring the tool you've chosen correctly and matching it to your actual use case.

ChatGPT — Verify Your Training Opt-Out

OpenAI uses [thirstylink ids="1031"]AES-256 encryption at rest and TLS 1.2+ in transit, per their security documentation. For Enterprise customers, Enterprise Key Management (EKM) lets you control your own encryption keys — a meaningful upgrade over standard encryption where OpenAI holds the keys.

If you're on Plus ($20/month) or the free tier: go to Settings → Data Controls and disable "Improve the model for everyone." This stops training on your conversations but doesn't delete past data already collected. For teams handling anything sensitive — source code, financial data, legal drafts — upgrade to ChatGPT Business ($25/user/month) or Enterprise where training opt-out is the default and you get admin controls, SSO, and usage analytics.

Claude — Understand the Consumer vs. Business Split

Anthropic's business plans (Team at $25/seat/month standard or $150/seat/month premium, Enterprise, and API) never train on your data — this is the default, no toggle required. For Pro ($20/month) and Max ($100–$200/month) users, you must opt out of training manually, and even then, data is retained for 30 days before deletion.

The practical move: if you're a solo professional handling client-sensitive work, the Pro plan with training opted out gives you 30-day retention and no model training. If you're a team, Claude Team Standard at $25/seat/month gives you privacy by default — no configuration needed. That default-private architecture is Anthropic's strongest selling point for privacy-conscious buyers.

Copilot — Fix Permissions Before You Deploy

No amount of Microsoft policy can protect you from your own SharePoint permissions. Before rolling out Copilot:

1. Run a permission audit using Microsoft Purview or a third-party tool like Concentric AI's data security posture management
2. Remove "Everyone except external users" from all sensitive SharePoint sites and folders
3. Apply Microsoft Purview Information Protection labels to confidential documents — Purview applies these encryption labels and enforces usage rights
4. Enable Restricted SharePoint Search to limit which sites Copilot can index
5. Review permissions quarterly — permission drift doesn't stop after one cleanup

This audit should happen before you activate Copilot licenses, not after. Once Copilot is live, every over-permissioned file is instantly searchable by every licensed user.

Security Certifications and Compliance

Certifications tell you how seriously a vendor takes security infrastructure. They don't guarantee your data won't be misused — but they do mean an independent auditor verified that specific controls exist.

OpenAI holds the broadest certification portfolio of the three. They also hold ISO/IEC 27001:2022 (information security management) and ISO/IEC 27701:2019 (privacy information management) for API, Enterprise, and Edu products.

Anthropic holds SOC 2 Type 2 certification, confirming that independent auditors have reviewed their security controls. For organizations where regulatory compliance drives vendor selection (healthcare, financial services, government), this gap matters.

Microsoft Copilot inherits the M365 compliance framework, which includes SOC 2, ISO 27001, HIPAA, FedRAMP, and dozens of other certifications that apply to Azure and M365 infrastructure. This is the broadest compliance surface of any of the three — but it applies to the platform, not specifically to Copilot's AI processing layer. The distinction matters: M365's certifications cover data storage and access controls, but Copilot's AI inference layer (powered by Azure OpenAI Service) carries its own risk profile.

A practical framework for choosing based on your compliance needs:

• Healthcare (HIPAA required): ChatGPT Enterprise or API with BAA, or Copilot via M365's HIPAA coverage.
• Financial services (SOC 2 + data residency): ChatGPT Enterprise (SOC 2 Type 2 + ISO 27001) or Copilot (M365 compliance boundary). Claude's SOC 2 covers this, but verify data residency requirements.
• Legal (confidentiality paramount): Claude Team/Enterprise (privacy-by-default, no training) or ChatGPT Enterprise (zero retention API option + EKM). Copilot only if your M365 permissions are airtight.
• General business: Any of the three on a business-tier plan. The differentiator is your existing infrastructure — M365-heavy shops may prefer Copilot's integration, but only after a permission audit.

One stat puts the governance gap in perspective: 81% of organizations say generative AI (GenAI) providers are transparent about data practices, but only 55% require contractual terms defining data ownership and liability, according to Cisco's 2026 Data Privacy Benchmark Study. Certifications are a floor, not a ceiling — and most organizations aren't even requiring the contractual protections that make those certifications enforceable.

The One Thing That Actually Protects Your Data

Every vendor comparison eventually lands in the same place: the tool doesn't protect you — your configuration does. Pick the plan tier that matches your sensitivity level (business or API for anything confidential), verify your training opt-out settings today, and if you're deploying Copilot, audit your M365 permissions before you flip the switch. Open your AI tool's privacy settings right now and confirm training is disabled. It takes 30 seconds, and it's the single highest-ROI security move you'll make this week.

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Found an error? At Canopy Press, accuracy comes first. If you spot a claim that needs checking, let us know at [email protected] — we'll verify and correct it immediately.

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Sources

• NIST