UPDATE (8th January 1:20 p.m. EST): CoinMarketCap has stated that it excluded the three Korean exchanges from their averages "due to the extreme divergence in prices from the rest of the world and limited arbitrage opportunity."

This morning we excluded some Korean exchanges in price calculations due to the extreme divergence in prices from the rest of the world and limited arbitrage opportunity. We are working on better tools to provide users with the averages that are most relevant to them.

— CoinMarketCap (@CoinMarketCap) January 8, 2018

CoinMarketCap, perhaps the go-to source for cryptocurrency market data, has sparked an uproar after it moved to exclude South Korean exchanges from its price average calculations.

The unannounced move to remove data from Bithumb, Coinone and Korbit from its average calculations sparked confusion given that its front-page suggests a broad decline in the cryptocurrency market, including what appeared to be a near-30% fall in the price of XRP.

The overall market cap of the market – one measure by which traders assess the ecosystem – dropped sharply once the change went into effect, which appears to have taken place just before 5 a.m. UTC.

That shift can be notably seen in the 24-hour price chart for bitcoin cash, given that the three Korean exchanges are among the top-10 by trade volume for the cryptocurrency.

The exact reason for pulling the data isn't clear at this time, though as of press time Bithumb is offline because of what the exchange says is a server check. And prices on those exchanges have consistently traded far above the rest of the market, such as the more than $5,000 spread spread compared to markets like Bitfinex and GDAX.

Further, commentators like Ripple chief cryptographer David Schwartz, who tweeted out about the move, said the newly-reflected price is "more accurate and meaningful."

That sentiment hasn't spared CoinMarketCap from the crypto-community's ire, however.

Social media posts across Reddit and Twitter have chastised the site, crying foul about the lack of any formal announcement that they say led to an actual price decline as traders reacted to what they perceived as a tumbling market.

And while CoinMarketCap excluded Korean exchanges from its data, other data sites showed similar declines in asset prices.

OnChain FX's

data matched CoinMarketCap's prices, yet CoinCap, while still showing declines in pricing for most of the top 50 crypto-assets, displayed higher prices for bitcoin, ether, XRP and bitcoin cash than CoinMarketCap did.

Similarly, data site LiveCoinWatch showed bitcoin falling to $14,787, somewhere between CoinMarketCap' $14,754 and CoinCap's $15,596 at time of writing.

The changes in the different sites' data go beyond just prices. Whereas LiveCoinWatch still shows XRP as the second-largest asset by market cap, the other data sites now show ethereum retaking its former spot.

Representatives for CoinMarketCap did not immediately respond to a submitted request for comment.

Disclosure: CoinDesk is a subsidiary of Digital Currency Group, which has an ownership stake in Ripple. 

Image via Shutterstock, graphs via CoinMarketCap.