The CEO of Apple Tim Cook, the Co-founder of WeWork Adam Neumann, and Ken Griffin the CEO of Citadel have been talking about cryptocurrencies among several other subjects during the DealBook Online Summit that the New York Times hosted this week.

For instance, Tim Cook announced that he invested in cryptocurrencies as a part of his personal financial investments. Meanwhile, Griffin spoke about the GameStop meme-stock based saga earlier this year.

Cook revealed he's personally invested in crypto, Neumann touted WeWork's prospects in the post-pandemic world, and Griffin reflected on getting caught up in the GameStop saga earlier this year.

10 best quotes from Cook, Neumann, and Griffin:

TC: "I wouldn't invest our cash balance in crypto. I don't think people buy Apple stock to get exposure to crypto."

TC: "I do, yeah. I think it's reasonable to own it as a part of a diversified portfolio. I've been interested in it for a while, and I've been researching it." - answering a question about whether he personally owns any crypto.

AN: "When the whole world is telling you that, yes we believed, and we thought it was really happening." - reflecting on how he accepted WeWork's $47 billion valuation as a private company. Its market capitalization is below $7 billion today.

AN: "Co-working in the time of corona is not the world's best idea. Flexible offices and community in the post-corona world, when work has shifted, might turn out to be one of the best ideas."

AN: "WeWork is a public company, it's valued in the billions of dollars, and it's positioned to be a real winner. If you're gonna say that it's a house of cards or it's a fraud, that's just false."

AN: "We've gotten pretty excited about crypto over the past half a year." - Neumann said his family office initially invested in three crypto-exposed companies, and he and his team have since looked at DeFi and Klima, a carbon-capture protocol.

KG: "We're seeing a market that is showing signs of real frothiness. We've got some pretty significant stock-price moves on relatively small events. I worry that as we move away from fundamental values, as multiples become incredibly high, any form of either policy error or a company having a bad spell is going to result in a pretty dramatic repricing of equities."

KG: "We don't want tax policy to drive great entrepreneurs like Elon Musk out of their seats. Part of what has made America a great source of innovation is the fact that our entrepreneurs are well-rewarded for what they create." - cautioning against raising taxes on billionaires.

KG: "People are very focused in a world of new ideas and new creations. I love that part of America. I worry that some of this passion is misplaced when it comes to cryptocurrencies." - Griffin raised concerns about crypto's fraud risk and energy consumption, and the difficulty of valuing it.

KG: "The whole GameStop conspiracy theory, it was fascinating to be in the middle of that. This is like a bad comedy joke, it's like a Saturday Night Live skit but in real-time." - GameStop investors accused Griffin and Citadel of abusing their market power, but a Securities and Exchange Commission report on the incident found no evidence of that and debunked several conspiracy theories.