Investing.com - Investors frustrated by the stock market's fits and starts, might want to take a look at commodities.Goldman Sachs (NYSE:GS) thinks the time is now, saying "the strategic case for owning commodities has rarely been stronger."In a note to clients, the firm notes that commodities have been hitting multi-year highs and have already returned 8% so far this year. Stock prices, meanwhile, are essentially flat.Goldman says strong global economic growth has created an equation of declining inventories and growing demand. The firm, which has been overweight in commodities since 2016, recommends "large allocations" to the sector. The firm recently said it was bullish on gold for the first time in five years, saying it expected it to outperform in a rising interest rate environment.