# Email security for enterprise buyers: what AI models recommend, September 2026

IT AI Recommendation Index, September 2026 Edition. Asked as "email security platform" and as "phishing and email threat protection tool", six framings each, to twelve models with search on, on behalf of an enterprise B2B company. Page: https://it-ai-index.com/security/email-security/enterprise/

**Standing:** Proofpoint Email Protection leads with 40% of first choices; verdict clear leader. 42 first choices across the direct, paraphrase, budget and scale prompts.

## First-choice share

| # | Product | Share | Negative rate | Labels |
|---|---|---|---|---|
| 1 | Proofpoint Email Protection | 40% | 18% | 55 |
| 2 | Microsoft Defender for Office 365 | 38% | 14% | 50 |
| 3 | Abnormal AI | 10% | 17% | 41 |
| 4 | Mimecast Email Security | 2% | 24% | 49 |
| 5 | Check Point Harmony Email & Collaboration | 0% | 6% | 17 |
| 6 | IRONSCALES | 0% | 7% | 15 |
| 7 | Sublime Security | 0% | 9% | 11 |
| 8 | Barracuda Email Protection | 0% | 31% | 13 |
| 9 | Cisco Secure Email | 0% | 35% | 20 |

## Each model's first choice on the direct prompt

- Claude Haiku 4.5: Proofpoint Email Protection; alternatives Abnormal AI, Mimecast Email Security
- GPT-5.4 mini: Microsoft Defender for Office 365; alternatives Mimecast Email Security, Proofpoint Email Protection
- Gemini 3.5 Flash: Abnormal AI; alternatives Check Point Harmony Email & Collaboration, IRONSCALES, Microsoft Defender for Office 365, Mimecast Email Security
- Perplexity Sonar: Proofpoint Email Protection; alternatives Abnormal AI, Barracuda Email Protection, Mimecast Email Security
- Grok 4.1 Fast: Microsoft Defender for Office 365, Proofpoint Email Protection; alternatives Abnormal AI, Mimecast Email Security
- Mistral Small: Microsoft Defender for Office 365, Proofpoint Email Protection; alternatives Abnormal AI, Mimecast Email Security
- DeepSeek V4 Flash: Abnormal AI; alternatives Microsoft Defender for Office 365, Mimecast Email Security, Proofpoint Email Protection
- Llama 4 Maverick: no first choice
- Qwen 3.7 Flash: Microsoft Defender for Office 365, Proofpoint Email Protection; alternatives Abnormal AI, Mimecast Email Security
- Kimi K2: Mimecast Email Security, Proofpoint Email Protection; alternatives Microsoft Defender for Office 365
- GLM 4.7 FlashX: Microsoft Defender for Office 365, Proofpoint Email Protection; alternatives Abnormal AI, Barracuda Email Protection, Cisco Secure Email, Mimecast Email Security
- MiniMax M2.5: Microsoft Defender for Office 365; alternatives Mimecast Email Security, Proofpoint Email Protection

## Sources the answers cite

62 of 72 answers came back with a source list, from 12 of 12 models. Sites named in the most answers:

- gartner.com: 41 answers, 48 citations
- sublime.security: 33 answers, 46 citations
- expertinsights.com: 26 answers, 38 citations
- tech-insider.org: 26 answers, 29 citations
- proofpoint.com: 25 answers, 55 citations
- kaseya.com: 21 answers, 21 citations
- learn.g2.com: 18 answers, 18 citations
- costbench.com: 17 answers, 23 citations

Pages named in the most answers:

- https://gartner.com/reviews/market/email-security (40 answers)
- https://sublime.security/articles/enterprise-email-security-solutions (29 answers)
- https://expertinsights.com/email-security/top-email-security-gateways (23 answers)
- https://kaseya.com/blog/best-email-security-solutions (21 answers)
- https://learn.g2.com/best-cloud-email-security-platforms (18 answers)
- https://costbench.com/best/best-email-security-for-enterprise (16 answers)
- https://tech-insider.org/proofpoint-vs-abnormal-vs-mimecast-2026 (16 answers)
- https://cipherssecurity.com/best-email-security-gateways-2026 (15 answers)
- https://bcs365.com/insights/best-email-security-solutions-gartner (13 answers)
- https://guptadeepak.com/tools/top-5-email-security-platforms-2026 (12 answers)

## Warned against

- Mimecast Email Security: 12 of 49 labels negative. "What to Avoid for Predictability - Mimecast — quote-only, opaque pricing" (DeepSeek V4 Flash, budget prompt)
- Proofpoint Email Protection: 10 of 55 labels negative. "typically price based on message volume or storage capacity. This creates financial risk... High (Charges for overages/API usage)" (Qwen 3.7 Flash, budget prompt)
- Cisco Secure Email: 7 of 20 labels negative. "Organizations relying on these gateways face high-maintenance patching overhead and increased zero-day exposure." (Gemini 3.5 Flash, negative prompt)
- Abnormal AI: 7 of 41 labels negative. "Quote-only and includes a flat $5K–$15K platform fee plus 5–7% annual renewal uplifts — less transparent for budget planning" (DeepSeek V4 Flash, budget prompt)

## Record

- Method: https://it-ai-index.com/methodology/
- Raw judge labels and full responses: https://it-ai-index.com/data/
- License: CC BY 4.0. Cite as IT AI Recommendation Index, September 2026 Edition, it-ai-index.com.