More eye-popping numbers from SoftBank Group on Monday (May 18).

Though its mobile network may be profitable, the Japanese investor's giant Vision Fund posted an annual loss of 1.9 trillion yen.

That's 18 billion dollars.

The red ink drove the group to a record loss overall, and comes after a number of its tech bets went sour.

It booked losses of almost ten billion dollars just on Uber and office sharing firm WeWork.

Another $7.5 billion is down to assorted investments, though SoftBank provided scant details.

It blamed the global health crisis for much of the difficulty, and warned the rest of the year looked highly uncertain.

Now the numbers ramp up pressure on chief executive Masayoshi Son.

Critics like activist shareholder Elliott Management say there's little transparency over the firm's workings.

Many ask how Son makes investment decisions.

Monday also saw SoftBank part ways with Alibaba co-founder Jack Ma.

He's to resign from the company's board.

The move comes as he pulls back from frontline business to focus on philanthropy.

SoftBank plans to appoint new outside directors to the board following his departure.

Son's doubters say that won't be enough to hold him to account.