Permanent Portfolio (25 stocks/25 bonds/25 gold/25 cash)

I just found out about the "permanent portfolio", each 25 represents the allocation to an asset class: a quarter to stocks, bonds, gold and cash. What is the Boglehead position on this?

I am copy pasting from the Economist article (it is pay-walled) but it seems unusually effective:

Since the start of 2025, tracking America’s S&P 500 share index would have returned 14%, compared with 10% for the classic 60/40 split between shares and Treasury bonds. A permanent portfolio constructed with American shares and Treasuries, meanwhile, would have delivered a 16% gain, calculate analysts at Bank of America. Moreover, since the start of the 2020s, the permanent and 60/40 portfolios have generated roughly the same returns, of 9% a year. Broaden the scope to global assets, and the permanent portfolio has returned 8% a year, while the 60/40 has returned 6%.

...the permanent portfolio is designed so that at least one of its parts ought to prosper whatever the weather. Proponents define four archetypal regimes—expansion, deflation, inflation and recession—which in combination can describe any economic backdrop. In an expansion, goes the reasoning, share prices should rise as earnings beat expectations. Deflation favours bonds, raising the real value of their fixed cashflows while falling interest rates raise their prices. Gold is the time-honoured inflation hedge, and cash is handy in a recession, both because you will need it if you lose your job and because you can use it to snap up assets at bargain prices.

What is more, history suggests that the permanent portfolio offers more than just a series of hedges against various economic hardships. A study in 2014 by Hamish Anderson, Ben Marshall and Jia Miao, all of Massey University in New Zealand, calculated 40 years’ worth of monthly returns for 11 permanent portfolios, each using stocks and bonds from a different country. In all cases, they found the losses made by permanent portfolios in the worst 5% of months were less severe than those from 70/30 splits between stocks and bonds. More surprisingly, the 25/25/25/25 strategies’ risk-adjusted returns—measured by the “Sharpe ratio” used by fund managers fine-tuning their portfolios—were always better.

Seems interesting.