A

Anthropic

Builds Claude AI models with a focus on safety

Anthropic Fellows Program - Reinforcement Learning

InternshipPosted on 4/10/2026
$3.9k/wk
Bachelor's
London, UK+2 moreMore locations: San Francisco, CA, USA | Ontario, Canada
HybridRemote fellows in the UK, US, or Canada may be possible.
AI & Machine LearningApplied Machine Learning, AI Research

About the job

Requirements
  • Fluent in Python programming
  • Available to work full-time on the Fellows program
  • Work authorization in the US, UK, or Canada and be located in that country during the program
  • Minimum education: Bachelor’s degree or an equivalent combination of education, training, and/or experience
  • Required field of study: A field relevant to the role as demonstrated through coursework, training, or professional experience
  • Program runs for 4 months, full-time
  • Logistics: Location-based workspace options include London and Berkeley; remote fellows in the UK, US, or Canada may be considered
  • Visa Sponsorship: Not currently able to sponsor visas for fellows
  • To participate in the Fellows program, you need to have or independently obtain full-time work authorization in the UK, the US, or Canada
Responsibilities
  • Fellows will undergo a project selection and mentor matching process
  • Projects in this workstream may include: Building model-based tools to better understand AI training data and improve training data quality
  • A research project to better understand generalization
  • Creating RL environments to improve Claude models at capabilities within your domain of expertise
  • Building RL environments for safety-related tasks
  • Conducting research and implementing solutions in areas such as RL algorithms
Desired Qualifications
  • Strong background in a discipline relevant to a specific Fellows workstream (e.g. economics, social sciences, or cybersecurity)
  • Experience in areas of research or engineering related to their workstream
  • Strong software engineering skills with experience building complex ML systems
  • Ability to balance research exploration with engineering rigor and operational reliability
  • Enjoy collaborating across research and engineering disciplines
  • Comfortable working with large-scale distributed systems and high-performance computing
  • Experience with training, fine-tuning, or evaluating large language models
  • Adept at analyzing and debugging model training processes

About the company

Anthropic builds the Claude family of AI models and sells them to businesses, software developers, and consumers, with research on making AI safe and understandable at the center of its work. In 2024 it introduced the Model Context Protocol, an open standard for connecting AI assistants to outside apps and data that OpenAI and Google adopted the next year. People use the Claude app to write and analyze files, programmers hand coding tasks to Claude Code, and companies build Claude into their own products through its API. Anthropic earns money from subscriptions, business plans, and usage-based API fees. Siblings Dario and Daniela Amodei founded Anthropic in 2021 with other former OpenAI employees, and it is based in San Francisco.

Company Size

5,001-10,000

Company Stage

N/A

Total Funding

$224.8B

Headquarters

San Francisco, California

Founded

2021

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Simplify's Take

What believers are saying

  • Sales are multiplying: Anthropic's yearly revenue pace topped $65 billion in July 2026, over sevenfold since December 2025.
  • IPO plans advanced: October 2026 reports describe investor meetings and a mid-November listing target; staff shares face lockups.
  • Lower office minimum: 627 of 646 Anthropic job posts in October 2026 require at least 25% office time.

What critics are saying

  • Job security rides on growth: Anthropic's IPO prospectus lists $518 billion in cloud and computing bills due in coming years.
  • Defense work stays off-limits: in September 2026, appeals judges voted 2-1 to let the Pentagon keep blacklisting Anthropic.
  • Growth is priced in: Anthropic's valuation reached $965 billion in May 2026, up from $380 billion in February.

What makes Anthropic unique

  • Investors don't control its board alone: Anthropic's independent Long-Term Benefit Trust elects a growing number of directors.
  • It isn't tied to one chipmaker: Claude runs on Nvidia GPUs plus custom AI chips designed by Google and Amazon.
  • It holds back its riskiest model: Claude Mythos 5.1, launched September 2026, goes only to vetted cyberdefenders and life scientists.

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Benefits

  • Flexible Work Hours
  • Paid Vacation
  • Parental Leave
  • Hybrid Work Options
  • Company Equity

Growth & Insights and Company News

Headcount

6 month growth

-3%

1 year growth

2%

2 year growth

-3%
Tech in Asia
Oct 17th, 2026
Anthropic leases Nova Scotia data center capacity in first Canada deal, tied to $7.3B EverWind project

Anthropic has signed a lease with EverWind for data center capacity at Point Tupper, Nova Scotia. It is the company's first such agreement in Canada, said Jacob Glick, Anthropic's Canada public policy head. EverWind, a Canadian developer of green energy projects, plans to invest more than C$10 billion ($7.05 billion) in the data center campus and related wind power projects. It has promoted the Cape Breton port area as a future clean fuel hub. Glick said Anthropic would protect ratepayers and water resources while ensuring local communities benefit.

TechCrunch
Oct 16th, 2026
Replit drops Anthropic for OpenAI over cost and performance, CEO says

Replit is no longer working with Anthropic, chief executive officer and co-founder Amjad Masad said Thursday at TechCrunch Disrupt. He cited cost, partnership and performance. "I think ChatGPT is better now," Masad said, adding that Replit's internal and public benchmarks show Sol and Astra build vibe-coded applications from scratch more effectively. Replit announced a partnership with OpenAI in August. An unnamed person familiar with the matter said the Anthropic partnership was still in place. A September blog post cited Anthropic's Claude models as running in Replit Agent's production environment. Masad said enterprise contracts made up about 15% of revenue this year, up from 2% last year. More than 50% of revenue is B2B.

Yahoo Finance
Oct 16th, 2026
Anthropic gets top junk credit rating from KBRA ahead of $35B chip financing

Anthropic received a double B plus issuer rating from Kroll Bond Rating Agency (KBRA) in June, the highest speculative-grade score and one notch below investment grade. The rating came before a $35bn chip financing led by Apollo, according to documents seen by the FT. Investment grade would lower the AI startup's borrowing costs and open it to investors such as pension funds and life insurers. Anthropic expects to spend more than $500bn on computing and infrastructure over the next decade. KBRA used a "risk score" because Anthropic withheld metrics including free cash flow. About $4.4bn of junior debt in the package carries Anthropic's credit risk and was sold at a yield of about 8.5%. Banks are now assembling a $60bn deal for more custom AI chips.

Yahoo Finance
Oct 15th, 2026
Claude's AI portfolio puts 14.5% in EMCOR as data centre demand lifts revenue 19.7%

Claude's AI stock portfolio holds 14.5% of its assets in EMCOR Group (NYSE:EME), its largest position. The portfolio is up 28.4% since late November 2025, against 15.3% for the S&P 500, according to the investing app Rallies. EMCOR installs power systems, backup generators, and cooling networks for data centres. Revenue rose 19.7% in the first quarter of 2026, with organic growth of 16.8%. The stock trades at a forward P/E of 24, against 19.1 for the S&P 500. Analysts expect earnings per share to rise 27% in 2026 and about 12% in 2027. Risks include order pauses, cost overruns, and slowing growth. The dividend yield is just 0.18%.

CNBC
Oct 15th, 2026
Cramer: AI stock storm, Fed rate hikes and Iran war risk test tech holders, with 12% in cash

CNBC's Jim Cramer says AI and data center stocks are under panic selling, as investors fear there is not enough money to fund the build-out. Anthropic's earnings fell short of expectations, though he noted its $100 billion annualised run-rate is hardly disappointing. Debt worries at thinly capitalised companies such as CoreWeave added to the fear. Nvidia chief executive officer Jensen Huang said on Thursday that CoreWeave is fine and its cost of capital is falling, which lifted tech stocks for the day. New Federal Reserve chairman Kevin Warsh may push short-term rates to 5.5% or 6% to bring inflation to 2%. They now stand at 3.75% to 4% after last month's hike, the first in three years. Cramer's investing club holds 12% in cash. It took profits in Cardinal Health, bought more Bank of New York, and favours high-quality stocks with strong balance sheets.

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