What happens if it all goes wrong? Investments designed to preserve your wealth in a stock-market downturn can help preserve your sanity too, allowing you to avoid dumping your favorite stocks as prices tumble.

When choosing a safe asset, it’s just as important to know who else owns it as to think about its fundamental properties. If they all sell in a panic, you’re stuck with something worth a lot less if you need to sell in a hurry.

Treasury yields don’t reliably move in the opposite way to stocks, as they did from the 1970s to the late 1990s.

"they can no longer be relied on to provide a sweet treat when stocks drop."

Gold has already been a big beneficiary. The price is up 50% in just over a year as investors bet on more buying by foreign central banks concerned about parking their money in dollars. This might be a problem. Unlike Treasurys and the dollar, gold ought to do well in a new era of inflationary pressure. But like Treasurys and the dollar, a lot of money has already poured in. How will it fare in a panic? Gold gained a similar amount in the 12 months to March 2008, as fears of financial troubles rose. But when first Bear Stearns and then Lehman Brothers failed, gold prices crashed from above $1,000 an ounce to just over $700, as investors sold to pay off debt.