SoftBank and Apollo have discussed setting up a large fund to invest in data centers, chip factories and other artificial intelligence projects. The two sides have discussed setting up a fund with a size of more than $20 billion, but talks have cooled since the summer and may not come to fruition, people familiar with the matter said. The joint venture fund could involve industry partners, including Arm, the people said. SoftBank has also held talks with other sources of financing, but the talks with Apollo are the most advanced, one person familiar with the matter said.