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US domestic sectors Global sectors Bond ETFs Commodity ETFs Commodity ETFs , also known as exchange-traded commodities ( ETCs ) , track a specific commodity index , such as : There are also commodity ETFs which track specific commodities , via commodity futures or mining companies .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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