The cryptocurrency market experienced a dramatic sell-off on January 9, 2018, after CoinMarketCap, the industry’s most widely used price-tracking website, abruptly removed several South Korean exchanges from its average price calculations without any prior notice. The sudden change wiped approximately $160 billion from the total cryptocurrency market capitalization within hours, sending shockwaves through an already volatile market.
TL;DR
- CoinMarketCap removed Bithumb, Coinone, and Korbit from price calculations without warning
- Total crypto market cap plunged from $830 billion to $669 billion, a 20% decline
- Bitcoin dropped to roughly $15,215, down 7% on the day
- XRP fell 25%, while Litecoin and Bitcoin Cash declined 11% and 13% respectively
- The removal exposed the fragility of crypto market data infrastructure
A Data Decision That Moved Markets
The controversy began when CoinMarketCap silently excluded three major South Korean cryptocurrency exchanges — Bithumb, Coinone, and Korbit — from its price averaging algorithm. South Korean exchange prices typically run 30% higher than those on exchanges in other countries due to the so-called “kimchi premium,” driven by strong local demand and limited arbitrage opportunities between Korean and international markets.
By removing these exchanges from the calculation, CoinMarketCap’s displayed average prices for major cryptocurrencies dropped instantly, even though actual trading prices on most global exchanges had not moved significantly. The sudden change in displayed prices triggered panic selling among investors who relied on CoinMarketCap as their primary price reference.
“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,” CoinMarketCap wrote on Twitter. “We are working on better tools to provide users with the averages that are most relevant to them.”
The Scale of the Sell-Off
The damage was swift and severe. The total market capitalization of all cryptocurrencies tracked by CoinMarketCap plummeted from approximately $830 billion to bottom out at $669 billion — a staggering 20% decline in a single day. By late Monday, the market had partially recovered to around $742 billion.
Bitcoin, which was trading around $14,595 according to CoinMarketCap’s historical data, fell to roughly $15,215 on other sources, down more than 7%. The altcoin market took an even harder hit. XRP, which had been surging in previous weeks, crashed 25%. Litecoin dropped 11%, and Bitcoin Cash fell 13%.
Community Backlash and Criticism
The move drew fierce criticism from across the cryptocurrency community. Many traders argued that CoinMarketCap should have announced the change in advance rather than implementing it silently. “Right, might be useful to notify people of things like this before or as you execute to avoid crashing the market, thanks,” one commenter wrote on Twitter.
On Reddit, the discussion took on a deeper tone. “How healthy is a market really if a single non-exchange website can crash it?” one user asked in a widely shared post. The incident raised fundamental questions about the maturity of cryptocurrency market infrastructure and the outsized influence of a single data provider.
Jordan Eliseo, chief economist at ABC Bullion, framed the episode as evidence of how undeveloped the crypto ecosystem remained. “The most obvious point is how undeveloped the ecosystem supporting bitcoin and cryptocurrency trading still is. It highlights the undeveloped nature of trading in bitcoin, reporting in bitcoin, market data sources for people to utilize when they’re wanting to track performance or monitor trends in that space.”
Regulatory Pressure Mounts
The CoinMarketCap incident coincided with a broader wave of regulatory uncertainty sweeping through the cryptocurrency market. Reports emerged that Chinese authorities were planning to abolish preferential electricity deals and tax deductions for bitcoin mining operations, threatening the profitability of one of the world’s largest mining hubs.
Bitcoin mining at the time consumed an estimated 38.6 terawatt-hours of electricity per year, according to Digiconomist — approximately 0.17% of total global energy consumption, exceeding the individual energy usage of countries like Denmark. The potential crackdown on Chinese mining operations added another layer of selling pressure to an already rattled market.
Meanwhile, South Korean regulators were signaling their own intentions to increase oversight on cryptocurrency trading, further contributing to the risk-off sentiment that defined the first full trading week of 2018.
Why This Matters
The CoinMarketCap episode of January 9, 2018 served as a wake-up call for the cryptocurrency industry about the dangers of concentrated data dependencies. A single website’s unilateral decision to change its methodology wiped out $160 billion in nominal market value — not because fundamentals changed, but because the lens through which investors viewed the market shifted overnight.
The incident foreshadowed debates that would continue for years about price discovery, exchange transparency, and the need for robust market data infrastructure in the cryptocurrency space. It also demonstrated that in early 2018, despite a combined market cap approaching $1 trillion, the crypto market remained profoundly fragile and susceptible to information asymmetry.
Disclaimer: This article is for informational purposes only and does not constitute financial advice. Cryptocurrency investments carry significant risk. Always conduct your own research before making investment decisions.