Just read Terry Smith's latest shareholder letter and honestly, it's raising some serious red flags about where we're headed. For those unfamiliar, Smith runs Fundsmith and gets compared to warren buffett a lot because he keeps his investment philosophy dead simple: buy good companies, don't overpay, do nothing. Pretty straightforward.

But here's what caught my attention - he's warning that we're building toward what he calls a major investment disaster. And it all comes down to one trend that's been quietly reshaping the market over the past two decades.

The shift to passive index funds has been massive. We're talking about trillions flowing from active management into low-cost index funds like the S&P 500 and Nasdaq Composite. On the surface, this sounds great - lower fees, simpler investing, everyone gets market returns. Even warren buffett has championed this approach for years.

But Smith's pointing out something most people are glossing over. When that much capital moves into passive funds, it creates this weird dynamic. The funds have to buy whatever's in the index regardless of valuation. Meanwhile, supply is basically fixed because companies are doing buybacks. So you get this situation where money flowing in doesn't actually reflect the intrinsic value of what you're buying.

The result? Market concentration on steroids. Mega-cap stocks keep getting bigger relative to everything else. And more importantly, prices become increasingly disconnected from what these companies are actually worth. An investment manager might think Tesla at 387 times trailing earnings makes zero sense, but if it's a huge index weight, shorting it could get them fired for underperformance. That career-preservation behavior is amplifying the distortion.

Smith's concern is that when sentiment eventually shifts - and it will - you could see a brutal and prolonged selloff. Not just a normal correction, but something more severe because the valuations are so stretched on these index darlings.

His solution? Go back to basics. Focus on quality companies trading at reasonable prices. The MSCI World Quality Index, which screens for high returns on equity and stable earnings, has historically beaten the broader market while offering better downside protection. It won't outperform every single year - warren buffett himself underperformed in roughly a third of his years at Berkshire Hathaway - but over 10-year periods, the math works.

The takeaway here is that just because something is the consensus move doesn't mean it's safe. Sometimes the crowd creates the very conditions that lead to disaster. Worth thinking about as you position your portfolio.