The AI Museum
AI Analytics1,072 recordsRecounted 23 September 2026

Open-weight language models in 2021

16

Models

12 organisations

100%

Open weights

16 open, 0 closed

1

Frontier

By Epoch's flag

1.6T

Largest traceable

Switch

2021

Span

12 with a traceable size

Releases

by month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sept
Oct
Nov
Dec

Records

16
Open-weight language models in 2021, newest first. Each row links to the source Epoch AI records for it.
ModelOrganisationReleasedParametersWeights
ContrieverMeta AI2021-12110M *Open
LongT5Google Research2021-123BOpen
XGLM-7.5BMeta AI2021-128BOpen
CodeT5-baseSalesforce2021-11220M *Open
base LM+GNN+kNNShannon.AI2021-10274MOpen
S4Stanford University2021-10249M *Open
PLATO-XLBaidu2021-0911BOpen
XLMR-XXLFacebook AI Research2021-0811BOpen
ERNIE 3.0Baidu2021-0710BOpen
DeBERTaMicrosoft2021-062BOpen
EMDRMila - Quebec AI (originally Montreal Institute for Learning Algorithms)2021-06440MOpen
ByT5-XXLGoogle2021-0513B *Open
Generative BSTFacebook AI Research2021-039BOpen
UnicornAllen Institute for AI2021-0311BOpen
SRU++ LargeASAPP2021-02234MOpen
SwitchGoogle2021-011.6TOpen

An asterisk marks a parameter figure the source does not consider traceable to the people who built the model. That judgement is the source’s and it has false negatives: Kimi K3 is marked speculative at 2.8T while Moonshot’s own model card states the figure. Why that distinction carries the whole exhibit.

Counts are of models Epoch AI records as notable, not of every model released. The most recent month is always incomplete, because a model enters the dataset when it is reviewed rather than when it ships.

Epoch AI, 'Data on AI Models'. Published online at epoch.ai. Retrieved from 'https://epoch.ai/data/ai-models-documentation' Used under CC BY 4.0.

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