SoftBank has provided half the money for a $400 million fund that will allow Abu Dhabi's state investment firm to invest in European start-ups.

The fund will help Mubadala to invest between $5 million and $30 million in individual start-ups, people briefed on the deal told the Financial Times which first reported the news.

Mubadala announced in June that it would create the $400 million fund to invest in European tech companies. It said at the time that SoftBank would participate as a strategic investor but did not disclose the extent to which it would contribute.