Investing legend Byron Wien says the stock market may be getting ahead of itself as the Dow passes 30,000 — but tells long-term investors not to worry

• Investing legend Byron Wien told CNBC that the stock market may be getting ahead of itself as the Dow passed 30,000 for the first time ever on Tuesday.
• "I'd have a degree of caution here," Wien said. "But I think we're in a long-cycle that's going to last several years." 
• The Blackstone Advisory Partners vice chairman said the economy will continue to expand and long-term investors will be rewarded if they're "patient."

Investing legend Byron Wien told CNBC that the stock market may be getting ahead of itself as the Dow Jones passed 30,000 for the first time on Tuesday.

"I'd have a degree of caution here," Wien said as the major index hit a record high. "I think the market with all the vaccines announced in the last two weeks may be getting a little ahead of itself, but I think we're in a long-cycle that's going to last several years."

The Blackstone Advisory Partners vice chairman said that the economy will expand for the next several years and this will help long-term investors realize gains.

"You may be paying a little too much now, but time will probably bail you out," Wien said. "If you're patient and hold on, you probably will be rewarded." 

The investor also said that persistent low-interest rates are likely to support a higher price-to-earnings ratio than the stock market has experienced in the past.

The record move in the Dow today is reflecting optimism that the economy will get back to normal as more progress on the vaccine front is reached, Wien added. 

The Dow is up nearly 56% from its lows in March and up 5% year-to-date. It reached its last major milestone—20,000—in the beginning of 2017.