According to people familiar with the matter who talked to Bloomberg News, Temasek invested between $200 million and $300 million in FTX before its demise. Temasek is now planning to write off the entire amount, according to one of the people who asked not to be identified because the matter is private. Another backer, Sequoia Capital, wrote down the full value of its $214 million bet on the exchange, while SoftBank Group Corp. is expected to lose around $100 million on its investment, according to a person familiar with the situation.