关税谈判关键时刻，孙正义提议设立美日联合主权基金，初始资本或达3000亿美元

Group 1 - The core idea of the news is that SoftBank founder Masayoshi Son is advocating for a significant joint sovereign wealth fund between the US and Japan, potentially starting with $300 billion in initial capital and leveraging it substantially [1] - The fund aims to make large-scale investments in the technology and infrastructure sectors of the US, with the US Treasury and Japan's Finance Ministry as joint owners and operators [1] - The proposal emerges during critical US-Japan trade negotiations, with Japan pushing for zero tariffs while the US maintains a baseline tariff of 10% [1] Group 2 - The joint fund is seen as a potential new revenue source for both governments without raising taxes, as it could provide a steady income stream [2] - There is an interest from the US Treasury to create a new sovereign-to-sovereign financial framework, while Japan seeks governance structures to protect against political fluctuations [2] - Masayoshi Son has been a key proponent of the fund and has previously collaborated with Trump on a $500 billion initiative aimed at developing US data centers and AI infrastructure [2]