SoftBank Group Corp. and Toyota Motor Corp. are considering additional investment of a combined $1 billion in Uber Technologies Inc., a source close to the matter said Thursday.

Toyota affiliate Denso Corp. is likely to join the investment which will be used to bolster the autonomous vehicle development division of the U.S. ride-sharing giant, the source said.

SoftBank is the largest shareholder in Uber Technologies, while Toyota injected $500 million into the company last August.

Uber Technologies filed for an initial public offering last week. The company is expected to list its shares on the New York Stock Exchange in early May with a valuation of $100 billion, according to U.S. media reports.

Honda Motor Co. has also been pushing ahead in the self-driving field, announcing in October last year that it will invest $2.75 billion in a project with General Motors Co.'s Cruise autonomous vehicle unit.