Agricultural commodities have proved significantly more popular than energy among buyers of exchange-traded products, despite the high-profile threats to oil supplies and Japan's nuclear reactor crisis.
Exchange-traded commodities and funds saw inflows of more than $600m in March, the fifth successive monthly increase, analysis by Societe Generale showed.
However, investors pared exposure to exchange-traded energy products by more than $500m, despite the month bringing continued tensions in the Middle East and North Africa, which bought New York oil prices to a two-year high during the month.
March also witnessed the Japanese earthquake and tsunami which, in leaving the Fukushima nuclear plant leaking radiation, provoked expectations of an improvement in demand for gas as a power source, lifting natural gas futures too.
On agricultural commodity futures markets, meanwhile, many investors reduced exposure last month, with grains saved from notable losses by a March 31 report which revealed US stocks significantly lower than investors had expected.
New York sugar prices fell more than 15% over the month.
Societe Generale attributed the "surprise" switch away from energy prices to "profit-taking or portfolio rebalancing... either to lock in some profits after a quarter of excellent performance and/or bring energy closer to target allocation".
Despite the sell-down, investors in exchange-traded products, which aim to offer an inexpensive, easy and liquid way of investing in assets such as commodities, held $12.5bn in energy, more than their $9.4bn exposure to crops.
On futures markets, a gain in investor interest in agricultural commodities after the March 31 US inventories reversed in the week to April 12, regulatory data released late on Friday showed.
Managed funds, a proxy for speculators, cut their net long exposure – that is long positions over above short holdings – in the main US-traded agricultural commodities by 21,932 lots below 950,000 lots over the week, Rabobank calculated.
Net long interest in Kansas wheat suffered a notable decline, down by 1,500 lots to less than 50,000 contracts, as rain forecasts lifted hopes for the rain-deprived US hard red winter wheat crop.
Soybean interest dropped to its second lowest point since June, thanks to "weak Chinese demand [for the oilseed] coupled with stabilising crop conditions in South America", Rabobank said.
However, managed funds lifted net-long exposure to Chicago corn, helping the grain to a record price over the week.
"It was the case of another week, another 30,000 contracts added to speculative net length," Australia & New Zealand Bank said.
"Since [late March], speculative net long positioning in corn has rebounded from 226,000 contracts to 297,000 contracts."