Microsoft Just Quietly Swapped the AI in Excel and Outlook — What Small Businesses Need to Know About the MAI Shift

What Microsoft Actually Did

On July 7, 2026, Bloomberg reported that Microsoft had begun routing tens of thousands of AI prompts per week in Excel and Outlook away from OpenAI and Anthropic models and onto its own in-house MAI (Microsoft AI) models. Not a test. Not a pilot. Live production traffic moving to models Microsoft built, trained, and runs itself.

The specific features affected include Copilot-assisted data analysis in Excel — generating formulas, surfacing trends, cleaning datasets — and email drafting, summarization, and scheduling in Outlook. These are the two highest-usage Copilot entry points for small business owners. And the AI underneath just switched teams without most users noticing.

Microsoft confirmed the move was driven by cost reduction, data residency control, and reducing dependency on external frontier model providers — even as it maintains its broader partnership with OpenAI. The message is clear: when it comes to the apps small businesses actually use every day, Microsoft wants full control of the stack.

The MAI Model Lineup: What’s Running Your Spreadsheets Now

At Microsoft Build 2026 in June, the company announced a family of seven MAI models covering reasoning, coding, image generation, voice, and transcription. The models relevant to the Excel and Outlook shift include:

• MAI-Thinking-1: A reasoning model designed for structured analysis — querying datasets, interpreting trends, generating formulas. This is the model most likely handling Excel Copilot prompts where the AI needs to “think” about numbers before responding.
• MAI-Code-1-Flash: A fast, cost-efficient coding model. Expanding from GitHub Copilot into broader Microsoft 365 features.
• MAI-Image-2 and MAI-Image-2-Efficient: Image generation models already rolling into PowerPoint and OneDrive.
• MAI-Transcribe and MAI-Voice: Speech and transcription models being tested in Teams and broader Copilot scenarios.

According to The Next Web’s coverage, MAI-Thinking-1 matches or approaches Anthropic’s Opus on key benchmarks at a fraction of the inference cost. For small business owners, that means the AI in your Excel sheet is now running on a Microsoft-owned model that’s as capable as the third-party alternative — at a price point that makes more features viable.

Why Microsoft Did This — and Why It Matters for Small Businesses

Three drivers behind the shift matter directly to SMBs:

1. Cost. Every Copilot prompt that runs on an OpenAI model carries a licensing cost for Microsoft. Moving tens of thousands of weekly prompts to MAI models running on Microsoft’s own Maia AI accelerators cuts that cost significantly. PYMNTS reported that Microsoft’s goal includes reducing and eventually eliminating spending on Anthropic entirely. Lower infrastructure costs for Microsoft means either better margins or — if the market demands it — lower Copilot pricing for customers.

2. Data Residency. When your Excel data leaves Microsoft’s infrastructure to hit an OpenAI API endpoint, even briefly, data governance gets complicated. Keeping everything on MAI models running inside Azure gives Microsoft (and by extension, its customers) tighter control over where business data lives and how it’s processed. For US-based small businesses handling sensitive client or financial data, this matters more than most realize.

3. Independence. Microsoft’s relationship with OpenAI is a strategic alliance, not a dependency. Building competitive in-house models reduces the risk of being held hostage by pricing changes, capability gaps, or strategic pivots from OpenAI. The MAI family is Microsoft’s insurance policy — and it just got deployed.

TechCrunch analysts noted that this shift positions Microsoft alongside Google and Meta as companies that control their own AI destiny rather than renting models from frontier labs.

What This Changes for Your Copilot Experience

If you’re a small business owner using Microsoft 365 Copilot in Excel or Outlook, here’s what’s different under the hood and what you should watch:

Speed. Early reports suggest MAI models running on Microsoft’s own silicon are faster for structured tasks like formula generation and data summarization. The inference pipeline is tighter — no third-party API calls, no external latency.

Quality. MAI-Thinking-1 benchmarks well against Anthropic’s Opus and GPT-4-class models on analytical reasoning. For spreadsheet work — pattern detection, anomaly flagging, formula creation — the model is purpose-built. For creative email drafting, the difference is harder to detect in day-to-day use.

Feature Velocity. When Microsoft controls the model, it can ship new Copilot features faster — no waiting for OpenAI to update an API, no retraining costs, no third-party roadmap dependency. This is the hidden advantage for SMBs: Microsoft can now iterate on its own terms.

What to keep an eye on: If you notice Copilot in Excel producing noticeably different results or Outlook email suggestions changing tone, check whether your tenant has been migrated. Microsoft is rolling this out gradually, and not all users will switch at the same time.

Is This a Good or Bad Thing for Small Businesses?

Short answer: net positive, with one caveat.

The upside: Microsoft’s in-house models are competitive, purpose-built for Office workflows, and cost Microsoft less to run — which should translate to either better pricing or faster feature development for SMB customers. Data stays on Microsoft infrastructure. The AI gets faster for the tasks you actually use daily.

The caveat: When Microsoft controls both the application and the model, vendor lock-in deepens. Moving to a competing suite becomes harder when your spreadsheet workflows depend on an AI that runs on proprietary Microsoft hardware and software. This isn’t a problem today, but small business owners should be aware that the cost of switching platforms goes up as the AI becomes more deeply embedded.

What Small Business Owners Should Do Right Now

1. Check if you’ve been migrated. Your Microsoft 365 admin dashboard will show which Copilot models are active. If you’re on a business or enterprise plan, check the Copilot settings for model selection options.

2. Test your critical workflows. Run your top five Copilot-heavy tasks through Excel and Outlook after the switch. If anything degrades, log it and track whether Microsoft’s iteration cycle fixes it. The MAI models are improving fast — early adopters are helping shape the roadmap.

3. Revisit your multi-model strategy. If you built workflows assuming Copilot runs on GPT-4 or Claude, those assumptions just changed. This is a good moment to test whether ChatGPT Enterprise, Claude Pro, or other tools fill gaps that MAI models might not handle as well — particularly creative writing or unstructured reasoning.

4. Watch the pricing. If Microsoft’s inference costs drop enough, Copilot pricing could adjust. Lock in annual plans if you see favorable terms. If costs don’t drop, start asking why — lower infrastructure costs should benefit customers.

What This Means for the Broader AI Landscape

Microsoft’s MAI move is the canary in the coal mine for the AI-as-a-service model. Every major platform company — Google with Gemini, Meta with the Muse family, Amazon with Nova — is building in-house models to replace third-party AI in their core products. The era of “rent the best frontier model and plug it into your app” is ending.

For small businesses, this is mostly good news: models get cheaper, faster, and more deeply integrated into the tools you already pay for. The risk is that you end up locked into an AI ecosystem that’s harder to leave than the software it replaced. The solution is the same as it’s always been — keep testing alternatives, keep your data portable, and never rely on a single AI provider for your entire operation.

Microsoft just showed its hand. The AI powering your Excel spreadsheets and Outlook inbox is now made by Microsoft. Whether that’s a competitive advantage or a lock-in risk depends on how you play it.

Frequently Asked Questions

Did Microsoft replace OpenAI models in Microsoft 365 Copilot?

Yes. Microsoft has begun routing tens of thousands of weekly AI prompts in Excel and Outlook from OpenAI and Anthropic models to its own MAI (Microsoft AI) family of models. The shift was confirmed by Bloomberg on July 7, 2026, and is expected to expand across more Microsoft 365 apps over time.

What are Microsoft’s MAI models?

MAI (Microsoft AI) is a family of seven in-house models announced at Microsoft Build 2026. They include MAI-Thinking-1 for reasoning and analysis, MAI-Code-1-Flash for coding, MAI-Image-2 for image generation, and MAI-Transcribe and MAI-Voice for speech and transcription tasks. These models run on Microsoft’s own Maia AI accelerators.

Will Copilot quality change after switching to MAI models?

MAI-Thinking-1 matches or approaches Anthropic’s Opus and GPT-4-class models on analytical reasoning benchmarks. For structured tasks like Excel formula generation and data analysis, users are unlikely to see quality drops. Creative tasks in Outlook may feel different, and Microsoft is iterating rapidly on model updates.

Should small businesses be concerned about this Microsoft AI shift?

Not immediately, but it’s worth monitoring. The shift could lead to faster features and lower costs for Copilot users because Microsoft controls the full stack. The risk is increased vendor lock-in as AI becomes more deeply embedded in Office workflows. Small businesses should test critical workflows and maintain multi-model options.

Will Microsoft stop using OpenAI entirely?

No. Microsoft continues its strategic partnership with OpenAI and offers GPT models through Azure. The MAI shift applies to specific Office app features where in-house models offer comparable quality at lower cost. OpenAI models remain available for other Microsoft AI products and customer deployments.

How can I tell if my Microsoft 365 account has switched to MAI models?

Check your Microsoft 365 admin dashboard under Copilot settings. Model selection and active provider information will show which models are handling your prompts. Microsoft is rolling out the transition gradually, so some tenants may still be on OpenAI or Anthropic models for certain features.