Making his case for why the bull market in stocks is not over yet, Byron Wien, vice chairman of Blackstone Advisory Partners, told CNBC on Wednesday that the fundamentals are sound but investors have become too complacent.
"The economy is doing well ... [and] the valuations are reasonable. So I think this is a correction in an ongoing bull market," Wien said in a "Squawk Box" interview.
Read MoreGlobal market rout continues; Greek stocks lose 4%
U.S. stock futures were lower in early trading, as concerns about Russia massing troops along the Ukrainian border continued to roil the markets, following Tuesday's triple-digit Dow Jones industrial average drop.
But even with the rough patch for the market, stocks are not even close to official correction territory—defined by a 10 percent decline from record highs.
As of Tuesday's close, the Dow is only off 4.21 percent from its intraday high on July 17 of 17,151. The is off 3.57 percent from its intraday high of 1,991 on July 24, while the Nasdaq composite index is down 2.97 percent from its intraday high of 4,485 on July 3.
Read MoreCramer: 2 stocks to buy on the way down
"There was too much optimism," Wien argued. "When everybody is feeling complacent and comfortable ... the market is vulnerable. And there's enough geopolitical influence to precipitate that."
—By CNBC's Matthew J. Belvedere