The outsized influence on the market of the so-called “FANG” stocks , high-growth tech names that include Facebook (FB), Amazon (AMZN), Netflix (NFLX) and Alphabet (GOOGL), doesn’t seem to concern economists Robert Shiller and Jeremy Siegel.

“A couple of those FANG stocks are selling for those triple-digit P/E ratios that could be a problem,” Siegel said. “And people say ‘well that does sound like 1999.’ But let me remind you in 1999, the tech sector of the S&P… was selling at 90 P/E ratio as a group. Today they are under 20x as a group. So yes a few are like those crazy high-fliers back then. But on the whole, we have nothing replicating what we had in 1999.”

Shiller added he doesn’t see risk of a sell-off in the names at this time, particularly given so many investment opportunities in the sector.

“The question is whether these tech stocks could decline suddenly. And I don’t see any reason to expect that right now,” Shiller said. “I think that we’re living in a time of fear about technology. People are being replaced by computers. Man, does everybody know that. That creates demand for investments of any sort. But I think people are especially enthusiastic about modern IT type investments and I don’t know that that’s going to go away.”

The risk, he added, really comes in the sphere of jobs.

“We’re going to continue to hear stories about computers replacing jobs,” Shiller added.

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