India's once-hot startup Byju's was valued at $22 billion. Now, HSBC and BlackRock say it's worth nothing.

• HSBC and BlackRock have written off their investments in once-hot Indian tech company Byju.
• The Indian education tech giant is facing legal and financial troubles.
• Investors, including Prosus, are trying to remove CEO Byju Raveendran.

In another blow to education tech giant Byju's, HSBC and BlackRock have both slashed their valuations of the once-hot company down to zero in recent months.

In 2022, the education tech company said it raised $800 million at a $22 billion valuation.