The question comes up every time the market wobbles: if a bear market is coming, should I be in VOO or VTI? A recent piece over at MSN works through the comparison, and the short answer is the one most people don't want to hear. Neither one is meaningfully safer than the other, because they're mostly the same fund wearing different coats.

Quick refresher. VOO tracks the S&P 500, the 500 largest US companies. VTI tracks the total US stock market, roughly 3,500 holdings. Sounds like a big difference until you realize VTI weights its holdings by market cap, and the megacaps at the top dominate both funds. Apple, Microsoft, Nvidia, Amazon, the same names sit at the top of each one. Over almost any stretch you'd care to measure, VOO and VTI have moved within a fraction of a percent of each other.

So what happens to each in a bear market? Roughly the same thing. Take the 2020 crash. The S&P 500 fell about 34 percent from its February 19 peak to its March 23 bottom, a little over five weeks, and a total market index rode down and back up on nearly the same schedule. If you own either one and a bear market arrives, you're going to watch a quarter to a third of your paper wealth evaporate for a while. That's the deal. That has always been the deal with owning stocks.

The theoretical case for VTI being slightly safer rests on the smaller companies it holds beyond the S&P 500, which is a modest slice of the fund by weight. More companies, more diversification. Except small caps aren't a shock absorber. Smaller companies tend to be more exposed to economic downturns than their larger counterparts, which is why that slice hasn't historically protected anybody in a crash. If anything it adds a bit of extra risk in a downturn, offset by a bit of extra return potential over decades.

I've written before about why VTI remains my default recommendation for most first-time investors, and I stand by that. But not because it's safer. Because it's simpler to explain and covers everything, which keeps people from tinkering. If you already own VOO, please don't sell it and switch to VTI out of bear market anxiety. You'd be trading a nearly identical fund for a tax bill.

A question worth sitting with instead: if a 30 percent decline in your portfolio next year would force you to sell, your problem isn't fund selection. Your problem is that you own more stock than your stomach can handle. The right amount of bonds and cash is the amount that lets you sleep through a bear market without touching the sell button. That decision moves the needle a hundred times more than VOO versus VTI ever will.

Pick one, automate your contributions, and stop rehearsing the escape plan. The investors I've watched succeed over forty years weren't the ones who picked the safer index fund. They were the ones who stayed in the building while it shook.

As always, this is my perspective, not professional financial advice. Talk to a fee-only advisor before making changes.