Freshly announced trade tariffs from the White House may be sending stocks into a tailspin, but a market correction is inevitable even without them, billionaire investor Jim Mellon told CNBC's "Worldwide Exchange" on Tuesday.

The trade war worries are "certainly having an effect on the market, but the market is reacting because it's already far too expensive," Mellon said. "The U.S. is selling at 32 times cyclically adjusted price-to-earnings (PE) ratio, which is an all-time high. Surely it's time for a major correction anyway."

Mellon is not alone in suggesting that today's stock market is the most overvalued on record — more so than in 1929, 2000 and 2007.

The chairman of asset management fund Burnbrae Group also pointed to over-complacency in markets and disproportionate buying of what he considered to be highly-inflated assets like tech stocks.

And according to the investing mogul, the trade fears are just an excuse for market players who were already looking to sell.

"There has been far too much complacency, far too many buybacks by corporations of their stock which have supported the market, far too much concentration of ownership, particularly in tech stocks in the U.S. And it's time for a very major correction, which is I think what we're embarking on."

Tuesday looks set to be a very rough day for stocks, with the Dow Jones and S&P 500 indexes at risk of losing the majority of their June gains at the open. The S&P has been down for three of the past four days. The Dow has fallen for the past five trading days — and the last time it fell for six straight days was in March 2017.