Microsoft 365 Copilot vs ChatGPT Business and ChatGPT Enterprise: Data Protection, Licensing and Which to Buy When You Already Run Microsoft 365

On the Microsoft side:

• Microsoft 365 Copilot Chat. Microsoft's pricing page, opened for this article, lists it as included at no additional cost with eligible Microsoft 365 plans: a web-grounded assistant, with organization-built agents usable on a metered basis. It answers from the web and files you give it, not your tenant at large.
• Microsoft 365 Copilot Business. For organizations up to 300 users on a Microsoft 365 Business plan: Copilot inside Word, Excel, PowerPoint, Outlook and Teams, grounded in your Microsoft 365 content through what Microsoft calls Work IQ. Microsoft list price, September 2026 price list: $252 per user per year on an annual commitment ($21 a month), or $25.20 a month on a monthly term.
• Microsoft 365 Copilot. The same Office-embedded Copilot for any size of organization: $360 per user per year on an annual commitment ($30 a month).

Our Copilot licensing and pricing guide covers prerequisites, bundles and pay-as-you-go; the Copilot Business trial article covers testing before buying.

On the OpenAI side:

• ChatGPT Business. The team workspace plan, renamed from ChatGPT Team on August 29, 2025 with no change to features (as reported by OpenAI's rename FAQ): an admin console, SAML single sign-on and OpenAI's business data terms.
• ChatGPT Enterprise. SCIM provisioning, role-based administration, a Compliance API with audit log export and regional data residency options (as reported by third-party comparisons; see Sources).

We do not print OpenAI's prices; they are per seat per month with minimums OpenAI quotes, and they change.

Microsoft. For Copilot Chat used with a work account and for Microsoft 365 Copilot, Microsoft's enterprise data protection documentation states that prompts and responses are processed within the Microsoft 365 service boundary, are covered by the same contractual terms as Exchange email and SharePoint files, are encrypted and tenant-isolated, and are not used to train the underlying foundation models or made available to OpenAI for training. (As reported by search excerpts of Microsoft Learn pages dated August 2026; Microsoft Learn was not reachable from our environment.)

OpenAI. OpenAI's business data page states that, by default, OpenAI does not use data from ChatGPT Enterprise, ChatGPT Business, ChatGPT Edu or the API platform, including inputs and outputs, to train or improve its models; that the customer owns its inputs and outputs; that business data is encrypted; and that business services are governed by the OpenAI Services Agreement and its Data Processing Addendum. (As reported by search excerpts opened 2026-09-27; the pages were not reachable from our environment.)

Side by side, the two training promises are close. The differences are where the data is stored, under which contract, and which of your systems can inspect it: Copilot's prompts and responses are Microsoft 365 data in your tenant; ChatGPT's are OpenAI data under a data processing addendum. Consumer ChatGPT plans work differently, and staff using personal accounts have none of these protections; see our shadow AI and Purview article.

Microsoft 365 Copilot's distinguishing feature is not the model; it is that it answers from your mail, files, chats and meetings through the Microsoft Graph, under the permissions the user already has, with citations. That is why the first Copilot problem in every tenant is oversharing: Copilot finds the salary spreadsheet a user could always open but never did. Purview controls before Copilot is the preparation; the Copilot ROI calculator frames the seat count.

ChatGPT started with no view of your tenant and has been closing the gap: ChatGPT Enterprise, and in part Business, now offers connectors to SharePoint, OneDrive, Outlook and Teams, including an admin-managed sync connector (as reported by Office 365 for IT Pros on October 13, 2025 and March 24, 2026). Two consequences: once a connector is authorized ChatGPT can see your data, so the same oversharing work applies; and that data leaves the Microsoft 365 boundary to be processed under OpenAI's terms.

For work about your own content (draft the reply, summarize the contract folder), tenant grounding wins on convenience and control. For work about the world (research, code, writing with a choice of models, custom GPTs), users often prefer ChatGPT, and Copilot Chat's web-grounded mode is the included alternative to try first.

Microsoft 365 Copilot and Copilot Chat are Microsoft 365 workloads, so the tenant's compliance tooling applies: audit records, eDiscovery and retention for prompts and responses, sensitivity labels honored during grounding, and a Purview DLP policy location for Copilot that stops it processing files with specified labels (as reported from Microsoft Learn). Conditional Access and Intune apply because the user signs in with Entra ID.

ChatGPT Enterprise can be brought under Purview. Microsoft's documentation describes registering the Enterprise workspace as a Purview data source with OpenAI's Compliance API and a collection policy in Data Security Posture Management for AI that captures prompts and responses into the tenant for audit, eDiscovery, retention, communication compliance and insider risk review (as reported). It captures after the fact rather than blocking, but an Enterprise workspace can be governed from the same Purview portal as Copilot.

ChatGPT Business has no Compliance API (as reported), so Purview cannot ingest its conversations; governance is limited to OpenAI's admin console and your endpoint and web controls. For a regulated organization that is the decisive difference.

1. Start with what is included. Turn on Copilot Chat for everyone and tell people to use it instead of a personal ChatGPT account for work data; block or monitor consumer AI sites with web filtering and Purview's AI controls.
2. License Microsoft 365 Copilot, or Copilot Business under 300 seats, for roles whose work lives in Outlook, Teams, Word and Excel, once the oversharing work is done; a measured pilot decides the count (how to run a Copilot pilot).
3. Add ChatGPT Enterprise, not Business, for teams that need a general model with model choice, custom GPTs or heavy research and writing, and connect it to Purview through the Compliance API.
4. Do not buy ChatGPT Business as the organization's AI platform if you are regulated. It suits a small, unregulated team; it is not governable from Microsoft 365.
5. Agents are separate spend. Copilot Chat agents, SharePoint agents and Copilot Studio are metered in Copilot Credits on an Azure subscription when used by people without a seat (as reported by Microsoft Learn); that charge is always yours and needs a budget alert.

For a typical 150-person professional services firm: Copilot Chat for all, Microsoft 365 Copilot for 40 to 60 seats, and either ChatGPT Enterprise for a 10-person team or no OpenAI contract. On Business Standard, the Business Standard with Copilot bundle article covers the math.

Is Microsoft 365 Copilot safer than ChatGPT?

The training promises are similar for the business plans. Copilot keeps prompts, responses and grounding inside the Microsoft 365 service boundary under your existing contract, and your Purview, Conditional Access and Intune controls apply without extra work. ChatGPT Enterprise can reach a comparable governed state through the Compliance API and Purview; ChatGPT Business cannot.

Can Purview see ChatGPT conversations?

For ChatGPT Enterprise, yes, once the workspace is registered with its Compliance API key and a DSPM for AI collection policy exists; prompts and responses then flow into audit, eDiscovery and retention (as reported). For ChatGPT Business and personal accounts, no.

Is Copilot Chat really included, or is there a catch?

It is included at no additional cost with eligible Microsoft 365 plans, per Microsoft's pricing page. The limit is what it can see: the web and the files you give it. Agents used by people without a Copilot seat are metered separately in Copilot Credits.

Should a 30-person company buy ChatGPT Business or Copilot Business?

If the work is in Outlook, Teams, Word and Excel, Copilot Business at $252 per user per year (Microsoft list price, September 2026 price list) reads your content and sits under your existing controls. If the work is research, writing and code with a preference for OpenAI's models, ChatGPT Business is fine for an unregulated team.

• Microsoft, "Microsoft Copilot Plans and Pricing" (microsoft.com/en-us/microsoft-365-copilot/pricing), opened 2026-09-27 (Copilot Chat inclusion; Copilot Business user cap; Work IQ grounding)
• Microsoft Learn, "Enterprise data protection in Microsoft Copilot and Microsoft Copilot Chat" (August 2026), "Microsoft Purview DLP for Microsoft 365 Copilot and Copilot Chat", "Use Microsoft Purview to manage data security & compliance for ChatGPT Enterprise" and "Microsoft Copilot Pay-as-You-Go Service Overview", as reported by search excerpts opened 2026-09-27; verify on Microsoft Learn
• OpenAI, "Business data privacy, security, and compliance" (openai.com/business-data) and OpenAI Help Center, "ChatGPT Business Rename FAQ" (rename effective August 29, 2025), as reported by search excerpts opened 2026-09-27; not opened directly; verify on openai.com
• Business versus Enterprise administrative differences as reported by Spotdev ("ChatGPT Business vs Enterprise: the controls gap") and IntuitionLabs ("ChatGPT Enterprise: Admin Controls & Security Settings"), search excerpts opened 2026-09-27
• Office 365 for IT Pros, "Enterprise SharePoint Connector Launched by OpenAI" (October 13, 2025) and "ChatGPT Enterprise Apps Grab Some Work IQ" (March 24, 2026), as reported by search excerpts opened 2026-09-27
• Microsoft Commercial price list, September 2026 (all list prices above)
• IT Partner service pages: content/services/ITPWW410CONOT, ITPWW210TRNOT and ITPWW380MSPRC; IT Partner blog articles linked above
• IT Partner engineering notes, September 2026