Billionaire investor Mike Novogratz blasted GameStop's valuation, warned against buying Dogecoin, and blamed the Fed for fueling speculation in a trio of interviews. Here are the 10 best quotes.

• Mike Novogratz called out GameStop and Dogecoin as examples of investor exuberance.
• The Galaxy Digital CEO argued bitcoin and Ethereum prices are much less frothy.
• Novogratz also criticized the Federal Reserve and suggested NFTs have peaked in price.
• See more stories on Insider's business page.

Billionaire investor Mike Novogratz questioned GameStop's valuation, warned against buying Dogecoin, and blamed the Federal Reserve for fanning market speculation in a recent trio of interviews.

The Galaxy Digital CEO also said that bitcoin and Ethereum look cheaper than other cryptocurrencies, predicted Dogecoin will plunge in price but won't disappear entirely, and suggested the hype around non-fungible tokens (NFTs) has peaked. He made the comments to CNBC, Yahoo Finance, and Bloomberg over the past week.

Here are Novogratz's 10 best quotes from the interviews, lightly edited and condensed for clarity:

1. "There's crazy excitement among very young investors around memecoins and meme ideas. It's shocking to me that GameStop continues to hold any value, let alone $10 billion or $12 billion in market capitalization. Dogecoin's even more bizarre in that respect."

2. "The real frothiness isn't in Ethereum, isn't in bitcoin, isn't in Coinbase, it's in smaller altcoins. Dogecoin is a meme coin that doesn't really have a purpose, yet it rallied up to a $50 billion market cap. There's lots of young people in the Reddit chatrooms that love Doge - both Elon Musk and Mark Cuban are pumping it up. I would be very worried if one of my friends was investing in Dogecoin at these prices."

3. "You've got to be very careful with Dogecoin, it's a dog."

4. "All of this is happening because interest rates are zero." - arguing the boom in speculative assets is a product of the Federal Reserve slashing interest rates, which has allowed cheap borrowing and made saving less attractive.

5. "Retail has the bit between its teeth in lots of ways. They're not giving up on GameStop, they're not giving up on Dogecoin right now. It's dangerous to be short, but I wouldn't be long either."

6. "I don't think Dogecoin will have legs. It's all retail and also there's nobody behind it, no institutions coming in, no strategic buyers, no one working on making Dogecoin a part of your portfolio. This is a retail phenomenon being driven by the fact that Fed Chair Powell is giving money to everybody. There's too much money in the system and it's driving asset prices up. You see these little crazy episodes from time to time."

7. "I do think the price of Dogecoin will head back much lower than it is as the energy gets lost. But I'm not positive it goes to zero. There will be some diehard Doge community that supports it somewhere."

8. "These coins are owned by communities. They're almost like European soccer teams: they have their own songs, their own mythos, their own vocabulary. If you're part of XRP, you're the XRP army, or if you own Luna, you're a Lunatic. They die more slowly than people predict."

9. "There are some pockets of retail froth and speculation. There is a retail frenzy, but it's not really being seen in bitcoin and Ethereum. Money's coming out of them and moving into other coins for more juice, more excitement."

10. "We've had some crazy prices in the NFT space. I don't think someone else is going to pay $69 million for a Beeple."