All tests of historical strategy performance (“backtests”) are imperfect reflections of the future. No one can say with certainty how stocks, bonds and other asset classes will perform in the coming years, but we have to root our analysis in something, and past performance is usually the best

Bonds are key to a well-diversified portfolio; they’ve provided both consistent returns and consistent diversification against riskier asset classes like stocks and real estate. But bonds face stiff headwinds in the coming years. That’s not prognostication, it’s a mathematical certainty.