Bitcoin’s November Rout Breaks a Seven-Year Monthly Record

Bitcoin finished November 30, 2018 with its steepest monthly decline in seven years, closing a month in which the market’s long-defended floor near $6,000 gave way and the leading cryptocurrency fell back to levels last seen in 2017.

CoinDesk’s Bitcoin Price Index put bitcoin at $3,964 at 00:00 UTC on December 1, after an average price of $6,341 at the start of November. On that measurement, the decline was 37.4%. Bloomberg, using its own market snapshot before the UTC close, reported bitcoin at $3,930 and down 37% for November. The small difference is expected: bitcoin trades continuously across venues, so index construction and observation time change the result.

A break in the 2018 market structure

The importance of the November move was not simply that bitcoin lost roughly $2,400 on the CoinDesk index. For much of 2018, repeated rebounds around $6,000 had encouraged the view that the post-boom decline had found a durable base. That proposition failed in mid-November. By November 30, 2018, the market was not only below that former floor but struggling to hold $4,000.

The comparison with August 2011 put the move in historical perspective. CoinDesk calculated that bitcoin had fallen about 40% in that earlier month, from roughly $8 to $4.80. Bloomberg’s contemporaneous comparison used a 39% August 2011 decline. Both records support the same bounded conclusion: November 2018 was bitcoin’s worst month since August 2011, though their precise percentages differ with datasets and endpoints.

Intraday reporting also shows why a single “price” should not be treated as universal. Reuters recorded bitcoin as low as $3,920.35 in late-morning trade on November 30 and described a fall of as much as 7% during the session. Bloomberg later recorded a 6.1% daily decline to $3,930. Those were time-stamped market observations, not a universal settlement price.

The damage extended beyond bitcoin

The selloff was broad. CoinDesk’s end-of-month review calculated an average November loss of 30% among the 10 largest cryptocurrencies by market capitalization and 37% among the largest 25. It found only one gain among that 25-asset group: bitcoin SV, which had only 22 days of CoinMarketCap pricing after the November 15 Bitcoin Cash split. That short history makes the apparent exception a poor comparison with assets traded for the full month.

Contemporaneous commentary offered possible explanations, including regulatory scrutiny, delayed infrastructure launches and disappointment after the $6,000 area broke. Those explanations were interpretations, not facts established by the price record. The verifiable result is narrower: prices declined sharply across the market, and bitcoin’s November loss set a seven-year monthly extreme.

What the data can and cannot show

The Federal Reserve Bank of St. Louis FRED series CBBTCUSD provides a separate daily U.S.-dollar bitcoin series sourced to Coinbase. It is useful as a venue-specific cross-check, but it is not the same instrument as CoinDesk’s multi-venue Bitcoin Price Index and does not erase differences among exchanges. Likewise, aggregate cryptocurrency volume and market-capitalization estimates in 2018 depended on exchange reporting and circulating-supply assumptions that were uneven across data providers.

The November 30 record therefore supports a firm statement about direction and historical scale, but not a claim that every holder could transact at one definitive closing price. Bitcoin had no centralized close. The cleanest reading is that the UTC month ended near $4,000 across major references, about 37% below the start of November, marking the sharpest monthly contraction since 2011.