15 years after the Dot-Com Bubble burst, the Nasdaq Composite Index leapt by 20.89 points, or 0.4%, to close at 5056.06 on Thursday, a record high. The strength of the index is being driven by the Silicon Valley 150 tech companies that have provided the juice to lift the NASDAQ by 6.8%, despite U.S. stock performance trailing major world markets.

At the start of this week, U.S. stocks were the worst performing major market in the world, with a 1.08 percent gain versus a 32.54 percent gain by China’s Shanghai exchange. But the NASDAQ has been moving up nicely, thanks to Silicon Valley tech IPOs that are now being called “Wall Street’s backbone and ATM.”

That type of language is reminiscent of the Dot-Com bubble high in March 2000, when the index hit 5132. But adjusted for inflation, the NASDAQ still is still down 31 percent from its peak. Instead of the Internet being all the rage in 2000, the new NASDAQ high is being driven by the rise of biotech and social media, as well as the explosive growth of mobile phones, which has helped make Apple the most valuable company in the United States.

Despite the recent gains, analysts claim from a valuation standpoint NASDAQ tech stocks are not anywhere near their speculative excesses at the peak of the Dot-Com Bubble. At its peak in March of 2000, there were 4,824 mostly small companies listed on the NASDAQ, and 65 percent of the index market capitalization was technology stocks. Today there are only 2,569 companies–mostly large ones–and tech is only 43 percent of capitalization.

The biggest difference is that the average NASDAQ stock price divided by earnings (P/E ratio) was 175 in 2000. That P/E ratio is 32 today, about the same as the past two decades.

Silicon Valley’s Apple shares led the way upward Thursday, with a +0.8 percent gain to $129.67, while Google tacked on +1.5 percent to close at $557.46. The NASDAQ strength lifted the Dow Jones industrial Average by 20.42 points, or 0.11 percent, to close at 18,058.69; and the S&P 500 gained 4.97 points, or 0.24 percent, to close at 2,112.93.

The Wall Street Journal quoted one leading trader: “The market saw pretty broad based strength, but it was not a frenzied day.”