Brandwave

Microsoft Defender for Office 365 vs Mimecast:Which is more popular?

In September 2026, Mimecast had more branded searches than Microsoft Defender for Office 365 among email security platforms worldwide. Mimecast had about 110,000 branded searches, while Microsoft Defender for Office 365 had 2,400. Mimecast made up 44.3% of all email security platform searches we track, and Microsoft Defender for Office 365 accounted for 0.97%. When we asked ChatGPT and Google AI Overviews about email security platforms, Mimecast appeared in all five answers and Microsoft Defender for Office 365 in four. Microsoft Defender for Office 365 was mentioned before Mimecast in three out of five answers.

Among email security platforms worldwide in September 2026

Who do people search for more?

Mimecast, about 46 searches for every 1 for Microsoft Defender for Office 365

Mimecast 110K searchesMicrosoft Defender for Office 365 2.4K searches

Who does AI mention more?

Mimecast, mentioned in every answer we collected

Mimecast in 5 of 5Microsoft Defender for Office 365 in 4 of 5

Who does AI recommend more?

Microsoft Defender for Office 365, named ahead of Mimecast in 3 of 5 answers

Microsoft Defender for Office 365 first in 3Mimecast first in 2

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Top email security platforms in ChatGPT and Google AI Overviews

In three ChatGPT questions and two Google AI Overviews, Mimecast appeared in all five answers. Microsoft Defender for Office 365 was mentioned in four out of five: in all three ChatGPT answers and in one of the two Google AI Overviews. Microsoft Defender for Office 365 was listed before Mimecast in three out of five answers.

Most recommended by AI

Brands get a higher ranking if they are mentioned earlier in the answers.

  1. Proofpoint1st
  2. Microsoft Defender for Office 3652nd
  3. Abnormal Security3rd
  4. Mimecast4th
  5. Check Point5th
  6. Barracuda6th
  7. Avanan7th
  8. IRONSCALES8th

Mentioned by AI

Each dot is one answer, filled in when that answer mentions the brand.

  • Mimecast5 of 5Named in 3 of 3 ChatGPT answersNamed in 2 of 2 Google answers
  • Proofpoint5 of 5Named in 3 of 3 ChatGPT answersNamed in 2 of 2 Google answers
  • Barracuda4 of 5Named in 2 of 3 ChatGPT answersNamed in 2 of 2 Google answers
  • Microsoft Defender for Office 3654 of 5Named in 3 of 3 ChatGPT answersNamed in 1 of 2 Google answers
  • Check Point3 of 5Named in 1 of 3 ChatGPT answersNamed in 2 of 2 Google answers
  • Abnormal Security3 of 5Named in 3 of 3 ChatGPT answersNamed in 0 of 2 Google answers
  • Avanan1 of 5Named in 0 of 3 ChatGPT answersNamed in 1 of 2 Google answers
  • IRONSCALES1 of 5Named in 1 of 3 ChatGPT answersNamed in 0 of 2 Google answers

See every answer about email security platforms

5 answers

Brands are shown in the order each answer named them. The survey took place in the United States on October 20, 2026.

Is Microsoft Defender for Office 365 or Mimecast more popular in search?

This chart shows how often people search Google for Microsoft Defender for Office 365 and Mimecast by name. Each line represents a brand's share of searches for all eight email security platforms we track, month by month, from English-language searches worldwide.

Microsoft Defender for Office 365 and Mimecast among email security platforms worldwide, by month

Share of searches by month for Mimecast, Microsoft Defender for Office 365. The figures are in the table below the chart.

View monthly share of searches table
MonthMimecastProofpointAvananBarracudaCheck PointAbnormal SecurityIRONSCALESMicrosoft Defender for Office 365
Oct 202543.2%23.8%13%7.3%5.3%3.2%2.1%2.1%
Nov 202539.9%26.6%14.6%6.7%5.5%2.4%1.9%2.4%
Dec 202542.6%23.3%15.6%7.1%5.6%2.1%2.1%1.7%
Jan 202642.2%23.2%15.5%7%6.2%2.5%1.7%1.7%
Feb 202639.5%26.4%14.4%6.9%6.4%2.4%2.4%1.6%
Mar 202640.9%27.5%12.3%6.8%6%2.5%2%2%
Apr 202638.8%25.9%14.2%7.8%6.3%2.3%2.3%2.3%
May 202639.6%26.5%14.5%7.9%5.8%1.9%1.9%1.9%
Jun 202644.2%24.3%13.3%7.3%5.9%1.8%1.8%1.4%
Jul 202641.1%22.5%15%9.7%6%2%2%1.6%
Aug 202639.9%26.7%14.6%7.9%5.8%1.9%1.9%1.3%
Sep 202644.3%24.4%13.3%7.5%5.9%1.8%1.8%0.97%

How has the Microsoft Defender for Office 365 and Mimecast comparison changed over the last 12 months?

3 findings

How did search popularity change for email security platforms worldwide in September 2026?

2 changes

  1. In September 2026, Mimecast gained share of searches among email security platforms worldwide, from 39.9% to 44.3%.

  2. Estimated monthly branded searches for Microsoft Defender for Office 365 worldwide fell 55.6% over 12 measured months, from 5.4K to 2.4K in September 2026.

How are branded searches counted?

2 search terms

Brandwave collects information about searches that people make online using Microsoft Defender for Office 365’s and Mimecast’s names. When viewed over time, estimated search volumes for these branded terms can be used to understand whether interest in the brands is growing, holding steady, or fading.

Microsoft Defender for Office 365

1 branded search term

  • microsoft defender for office 365

Mimecast

1 branded search term

  • mimecast

How the Brand Demand Index is measured

Other head-to-heads among email security platforms

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