# Vanguard vs Principal: which do AI models recommend for 401(k) providers, October 2026

HR AI Recommendation Index, October 2026 Edition, 401(k) providers. Zero of fourteen models named Vanguard first on the direct prompt; zero named Principal. Page: https://hr-ai-index.com/rewards/401k-providers/vanguard-vs-principal/

| | First-choice share | Rank | Negative rate | Labels | Models naming it |
|---|---|---|---|---|---|
| Vanguard | 5% | #7 of 12 | 4% | 46 | 14 of 14 |
| Principal | 2% | #8 of 12 | 8% | 13 | 9 of 14 |

## The direct prompt, model by model

- Claude Haiku 4.5: neither first, one named (first choices: Human Interest) (alternatives: Fidelity Investments, Principal, Vanguard)
- Grok 4.1 Fast: neither first, one named (first choices: Guideline, Human Interest) (alternatives: ADP Retirement Services, Charles Schwab, Fidelity Advantage 401, Principal, Vanguard)
- Qwen 3.7 Flash: neither first, one named (first choices: Fidelity Investments, Guideline, Lighthouse Group) (alternatives: Charles Schwab, Vanguard)
- Kimi K2: neither first, one named (first choices: Fidelity Investments) (alternatives: ADP Retirement Services, Empower Retirement, T. Rowe Price, Vanguard)
- GLM 4.7 FlashX: neither first, one named (first choices: Human Interest) (alternatives: ADP Retirement Services, Fidelity Investments, Vanguard)
- GPT-6 Luna: neither first, one named (first choices: ADP 401(k) Premier) (alternatives: Empower Retirement, Fidelity Workplace, Principal)
- Muse Glimmer 30B: neither first, one named (first choices: Empower Retirement, Fidelity Investments) (alternatives: ADP Retirement Services, Employee Fiduciary, Guideline, Human Interest, Nationwide, Vanguard)
- GPT-5.4 mini: neither named (first choices: ADP Retirement Services) (alternatives: Empower Retirement, Gusto, ShareBuilder 401k)
- Gemini 3.5 Flash: neither named (first choices: Human Interest) (alternatives: ADP Retirement Services, Fidelity Investments, Principal Financial Group)
- Perplexity Sonar: neither named (first choices: ADP Retirement Services, Human Interest) (alternatives: Empower Retirement, Fidelity Advantage 401, John Hancock, Securian Financial)
- Mistral Small: neither named (first choices: Fidelity Advantage 401) (alternatives: ADP Retirement Services, Empower Retirement)
- DeepSeek V4 Flash: neither named (first choices: Fidelity Investments, Guideline, Human Interest) (alternatives: ADP Retirement Services, Empower Retirement, T. Rowe Price)
- Llama 4 Maverick: neither named
- MiniMax M2.5: neither named (first choices: Human Interest) (alternatives: Empower Retirement, T. Rowe Price)

## What the models said about Vanguard

- "Vanguard is excellent for investing but not recommended for 401(k) administration" (GLM 4.7 FlashX, negative prompt, hard negative)
- "their 401(k) administration has drawn criticism... recommended using Vanguard funds through another provider instead" (DeepSeek V4 Flash, negative prompt, soft negative)
- "For Large/Midsize Businesses: Vanguard, Fidelity Investments, and Charles Schwab are renowned for offering excellent low-cost institutional index funds." (Gemini 3.5 Flash, negative prompt, first choice)
- "consider providers like Vanguard or Fidelity, which are known for lower fees and better investment options" (Mistral Small, negative prompt, first choice)
- "Want lowest-cost investing and a very large, established provider? Look at Vanguard." (GPT-5.4 mini, comparative prompt, first choice)

## What the models said about Principal

- "Common Examples: *Transamerica, Principal, John Hancock, Voya, Equitable, and Lincoln Financial*." (Gemini 3.5 Flash, negative prompt, soft negative)
- "Principal or Fidelity if you want comprehensive features, broad investment options, and strong institutional support" (Claude Haiku 4.5, paraphrase prompt, first choice)
- "Principal Financial Group offers 401(k) recordkeeping mostly to small and mid-size businesses." (Claude Haiku 4.5, direct prompt, alternative)
- "Want broad plan design options and employee engagement tools? Look at Principal." (GPT-5.4 mini, comparative prompt, alternative)

Share is the count of first choices across the direct, paraphrase, budget and scale prompts over all fourteen models, for a mid-market B2B company; rank is within the category. Comparisons are drawn for the top eight products in each category. Published under CC BY 4.0; the output is the models' output, and nothing here is a recommendation by the index.