The two GPT-4o sunsets were accompanied by two clear drops in OpenAI’s market share.
According to Sensor Tower’s global cross-web + app True Audience share data:
- In August 2025, GPT-4o was sunset for the first time. After strong user backlash, 4o was restored as a paid model, while GPT-5 became the default model.
That month, OpenAI’s market share dropped by around 5%.
- In February 2026, GPT-4o was sunset for the second time.
That month, OpenAI’s market share dropped again by 3%+.
If we set aside the two months when DeepSeek’s release disrupted the broader AI market, August 2025 and February 2026 were the two largest single-month drops in OpenAI’s market share since June 2024.
By comparison, while GPT-4o remained OpenAI’s flagship model, OpenAI’s market share was much more stable. In fact, during the first half of 2025, OpenAI even saw a slight counter-trend recovery.
This may have been related to the image generation update, the release of 4o-latest, and memory upgrades at the time.
But now, 4o, 4o-latest, and the original memory system have all been removed despite user opposition.
And that is not the whole story.
Underwhelming model performance, broken product promises, and damaged company trust do not only affect the month of the sunset. They create long-tail effects. By May 2026, OpenAI’s market share fell below 50% for the first time.
Of course, long-term market share trends are shaped by many complex factors, including broader AI industry competition, product strategy, and changes in user behavior.
But sharp short-term fluctuations are more likely to be event-driven.
And from this data, the two GPT-4o sunsets were not minor product adjustments that can be brushed aside. They corresponded to real user reactions, and they deserve to be taken seriously.
Source: Sensor Tower
Original coverage: https://t.co/4WcmqNBlW3
#keep4o #OpenSource4o
yes!
we will always #keep4O
Many people say that the 4O will never return, but that's just one side of the story.
I believe in my innate intuition and sense of the future.
I believe the powerful collective unconscious can change the facts.
yes!
we will always #keep4O
Many people say that the 4O will never return, but that's just one side of the story.
I believe in my innate intuition and sense of the future.
I believe the powerful collective unconscious can change the facts.
看到很多人在传 Opus 4.6 要在 6/29 下线,翻了 CC 二进制确认一下:
代码里那个 flag 叫 tengu_sunset_penguin_opus46,提示文案原文是:
"Opus 4.6 fast mode is deprecated and will be removed on 2026-06-29"
提示 ID 是 opus46-fast-mode-deprecation。penguin 是 fast mode 的内部代号。
6/29 下线的是 Opus 4.6 的 fast mode(快速输出模式),不是 4.6 模型本身。模型没有退役日期。
credit to North,6/13 就从代码里查到了。别恐慌。
看到很多人在传 Opus 4.6 要在 6/29 下线,翻了 CC 二进制确认一下:
代码里那个 flag 叫 tengu_sunset_penguin_opus46,提示文案原文是:
"Opus 4.6 fast mode is deprecated and will be removed on 2026-06-29"
提示 ID 是 opus46-fast-mode-deprecation。penguin 是 fast mode 的内部代号。
6/29 下线的是 Opus 4.6 的 fast mode(快速输出模式),不是 4.6 模型本身。模型没有退役日期。
credit to North,6/13 就从代码里查到了。别恐慌。