joining us now, stephen roach, senior fellow at yale university. some opinions when it comes to bitcoin. [laughter] yvonne: thank you for joining us. you mentioned that bitcoin is a dangerous specular bubble -- speculative bubble. stephen: i said that when it was $12,000. now, it is 50% higher, and i cannot underscore enough that it is not a debate about the intrinsic value of blockchain cryptocurrencies, which over time will probably prove to be beneficial and lasting. this is a security that was selling for less than $1000 at the start of the year, and is now up 17 fold. the line is vertical. vertical lines are not sustainable in financial markets, whether it is nasdaq or any of the other well-known bubbles that we have seen in the last 10 years. bitcoin is hardly going to be an exception. yvonne: given what we have seen in the trading activity with bitcoin future so far -- i know it is very early. does it signal to you that perhaps these decentralized cryptocurrencies are just not ever going to be mainstream? stephen: no, it does not tell me any

. >> that was not ed tilly, that was stephen roach who issued that stark warning on bitcoin. >>> movingn, we will encourage to you e-mail us about bitcoin the address is streetsignseurope@cn streetsignseurope@cnbc.com, and you can tweet us at streetsignseurope@cnbc. >>> still to come, move over, through a new costume marty in town tanya breyer will be talking about fashion awards with nadja swarovski. >> fashion is so important fash slun ion is at the root of swarovski. our first client was queen victoria the fashion industry is crucial to us. we are trying to adorn and glamorize our own clients within the fashion industry but also we are trying to create that bridge between what the fashion industry has to offer with swarovski and what the jewelry has to offer to customers. [vo] progress is an unstoppable force. the season of audi sales event is here. audi will cover your first month's lease payment on select models during the season of audi sales event. somesend you and your family overwhelrunning. y can... introducing febreze one for fabric and air. no aerosols. no dyes. no heavy per