[wc-]

The wash trading volume has nothing to do with tether (the trades are not even executing against the book in many cases, just reported as trades on the data feeds CMC consumes). Exchanges are using bots to wash trade back and forth on every trading pair to give the appearance of massive volume in an attempt to gain customers. It is very easy to see on charts and has nothing to do with propping tether up, whatever that means.

CoinMarketCap has been asked to exclude these exchanges from their volume reports for a long time and ignores them, most likely due to a conflict of interest (exchanges pay to advertise on CMC for example). Just like someone can create a new token and artificially inflate its market cap, exchanges can be created and artificially report their volume. CMC does nothing to filter this out and it results in a totally misleading view of the crypto markets.

OnChainFX is one example of an attempt to remove those wash-trading exchanges from the total volume reports.

My only reason for the inital reply was to urge people to not use CMC volume reports, there are better options out there that reflect real trading activity.