It’s the not the first time long-term wealth managers substantially raised their holdings of natural resources that, while volatile, offer a way to tap into an improving economy or hedge against inflation. In 2011, pension funds had about 3 percent to 5 percent of assets invested, but as prices ground lower through 2015 they scaled back or sold out entirely, Keenan said.

The memory of such losses may be enough to discourage some.

“There are no signs that I’ve seen that a new bull market is here or is close for commodities,” said John LaForge, the Sarasota, Florida-based head of real assets strategy at Wells Fargo Investment Institute, which oversees $1.7 trillion. “We’re probably at least five years away.”

Buying and selling of exchange-traded funds that allow investors to bet on individual or groups of commodities paint a conflicted view of demand. This month, data compiled by Bloomberg Intelligence showed $450 million was taken out of long-only ETFs connected to broad baskets of natural resources.

However, that figure is offset by the launch of the Source Bloomberg Commodity UCITS ETF with about $500 million of seed capital, excluded from the flow data because it’s a new fund.

Hedge Funds

While there have been about $80 million of withdrawals from gold, traditionally a hedge against economic weakness, there are signs investors are more optimistic on other individual raw materials. Energy ETFs attracted $390 million this month, following $2.65 billion of outflows in December. Investors added almost $40 million in industrial metals, while agriculture got $25 million.

Interest is being spurred by signs of a spreading pickup in the economy and inflation in the U.S., and a recovery in Chinese demand for raw materials. The Bloomberg Commodity Index rebounded last year from the biggest slump since the financial crisis.

"There are a lot of firms that have built up a fundamental basis for their views and they’re going to be looking at investing specifically in agriculture or metals, say, rather than index investment," Michael Cohen, Barclays’ head of energy commodities research, said by phone from New York.

Even hedge funds and other large speculators who report to the U.S. government are bullish on 15 of 18 raw materials tracked by the CFTC. The combined net-long positions across these 18 raw materials have risen in six of the past eight weeks, according to commission data tracked by Bloomberg.