To those caught in the still-inflating "Magnificent Seven" tech stock bubble, it's a worthy endeavor to remember there are 493 other potential equities to invest in within the S&P 500 (^GSPC). And outside of the S&P 500, there could be great investing opportunities in private equity, Treasurys, and hey, maybe even classic cars, if that's your thing. Put it all together, and this is what's known as diversification — a tried-and-true wealth-building approach tested by millionaires and billionaires alike, life and business strategist Tony Robbins touted. "I would just say maintain diversification.