Peg: Noun:
Economics. The level at which some price, exchange rate, etc., is set.
ZetaCE“Actually, how can we know whether it works as a noun or a verb ?”
Because it has an article for a start.
ZetaCE“The territory’s currency peg”
"
Territory's currency" is adjectival phrase within this noun phrase (well not exactly but let's look at it that way). If it is removed the sentence retains the same meaning. i.e. "
The peg to the US dollar is helping boost fund inflows." In this sentence you can probably now see it is clearly a noun.