{
  "commodities": [
    "gold",
    "iron_ore",
    "crude_oil"
  ],
  "producers": [
    "Vale",
    "BHP",
    "Rio_Tinto",
    "Saudi_Aramco"
  ],
  "contracts": {
    "gold": ["CME_GC", "LME_AU"],
    "iron_ore": ["SGX_FEF"],
    "crude_oil": ["NYMEX_CL"]
  }
}