這是業內人士說的，比較靠譜，我當然說的是Nominal Value，OTC很難清楚，所以巴菲特說是大規模殺傷性武器。

Since swaps are highly customized and not easily standardized, the swap market is considered an over-the-counter (OTC) market, meaning that swap contracts cannot typically be easily traded on an exchange. But that does not necessarily mean swaps are illiquid instruments. The swap market is one of the largest and most liquid global marketplaces, with many willing participants eager to take either side of a contract. According to the Bank for International Settlements, the notional amount outstanding in over-the-counter interest rate swaps was more than $341 trillion in 2019.1