---
id: "2025-01-20-deepseek-r1"
url: "https://postcutoff.com/e/2025-01-20-deepseek-r1/"
as_of: "2026-11-13T13:49:00+01:00"
date: "2025-01-20"
date_precision: day
category: open-source
importance: 5
confidence: high
status: [Confirmed]
sources: 3
editor: human editor
human_review: null
version: "2026-10-04"
---

As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/e/2025-01-20-deepseek-r1/

# DeepSeek-R1: open-weights reasoning model rivals o1 and shakes markets

DeepSeek released R1 under the MIT license, a reasoning model matching OpenAI o1 on math and coding benchmarks, and showed with R1-Zero that reasoning can emerge from pure RL; on 27 January 2025 it topped the US App Store and NVIDIA lost ~$589B in market value in a single day.

## Key facts
- Released 20 January 2025; paper arXiv 2501.12948
- MIT license, with distilled smaller models (1.5B–70B) based on Qwen and Llama
- R1-Zero trained with RL (GRPO) without supervised fine-tuning
- NVIDIA shares fell ~17% on 27 January 2025, erasing ~$589B — the largest one-day loss in US market history
- Peer-reviewed version published in Nature in September 2025

## What happened

DeepSeek openly published a reasoning model and its RL recipe; its free chatbot app went viral worldwide.

## Why it matters

The 'DeepSeek moment' showed that frontier reasoning could be replicated cheaply and openly, triggering a market shock, a wave of open reasoning models, and US policy debates on China.

## Your AI and this story

- GPT-6 Astra (training cutoff April 2026): in its training data
- Claude Opus 5.5 (training cutoff June 2026): in its training data
- Gemini 4 Hydrogen (training cutoff March 2026): in its training data
- Grok 4.7 (training cutoff May 2026): in its training data

## Sources

1. [DeepSeek-R1: Incentivizing Reasoning Capability in LLMs via Reinforcement Learning (arXiv)](https://arxiv.org/abs/2501.12948) (arxiv.org, paper)
2. [deepseek-ai/DeepSeek-R1 (code & weights)](https://github.com/deepseek-ai/DeepSeek-R1) (github.com, code)
3. [Nvidia sheds almost $600 billion in market cap (CNBC)](https://www.cnbc.com/2025/01/27/nvidia-sheds-almost-600-billion-in-market-cap-biggest-drop-ever.html) (cnbc.com, press)

## Changes

- 2026-09-29 (filed): Created

## Related

- 2024-12-26: [DeepSeek-V3: frontier-level open model trained for ~$5.6M in GPU time](https://postcutoff.com/e/2024-12-26-deepseek-v3/index.md)
- 2024-09-12: [OpenAI o1: reasoning models trained with reinforcement learning](https://postcutoff.com/e/2024-09-12-openai-o1/index.md)