"As someone who watched the bubble, was part of the bubble and am gloriously in print writing that I was selling the Nasdaq and moving into bonds during the second week of March 2000, a week before the absolute top, I think I have street cred to contrast the two moments," Cramer said.  Could the market really be headed toward a bubble?  To find out, Cramer compared the market then versus now to see if the situations are alike. First, there is the market leader, Apple. Cisco was the leader back in in 2000, with a market cap of $550 million. Apple now has a $736 billion market cap.  Yet anyone who follows Cramer knows that he values stocks by looking at their price-to-earnings multiple. While the average stock is trading at just 18 times earnings currently, Apple now sells at approximately 15 times earnings.  In the last bubble, Cramer argues that Cisco sold at about 80 times earnings. That is a huge difference!  Back in 2000, Cisco was up to a much different game than what Apple is accomplishing now. Back then, Cisco was the backbone of companies like MCI WorldCom and Nextel.  The companies it supported eventually disappeared and its client base dissipated. Cramer does not see the same thing occurring with Apple right now.  Google is next up, with a $370 billion market cap. And while Cramer does own the stock in his charitable trust, he's still concerned that it moves quickly yet is so slow to monetize assets.  "Let's face it, this stock acts like death and has forever. I don't think at 19 times earnings—and a lot less if you back out the cash—that you are dealing with anything expensive," Cramer added.  Microsoft was the second largest company back in 2000. Can it be compared to Google? No. It was indeed peaking at the time, and it also sold around 80 times earnings.  But it missed the boat on technology, unlike Google. Microsoft missed the social, mobile, cloud and open system movements. Now it is far from being overvalued, at 16 times earnings.  Similarly, Intel was also extremely expensive, along with Oracle and Sun. Today the biotechs like Gilead, Amgen, Celgene and Biogen are also helping to power the Nasdaq. Are they expensive? Heck no! Amgen is at 16 times earnings.  At the end of the day, there may be buzz about a bubble happening, but Cramer is not worried about it.  ---------------------------------------------------------- Read more from Mad Money with Jim Cramer Cramer Remix: This stock is on a run Cramer's game plan: Expect major news on this Cramer: The sexy stock giving you glamorous gains ----------------------------------------------------------  "I struggle to figure out why the Nasdaq isn't higher, why the valuations aren't bigger, especially given our low inflationary environment," said Cramer.  So, until he sees evidence of stocks being overvalued, or the 10-year Treasury yield even goes above 2 percent, he's not buying it. He will believe it when he sees it, and the proof is not in the pudding right now.
The market is reaching new highs, but could we really be in a bubble? Jim Cramer finds out.