What is the CoinDesk Bitcoin Price Index?
It is intended to serve as a standard retail price reference for industry participants and accounting professionals.
Which bitcoin exchanges does the BPI include?
The criteria for inclusion in the BPI are:
- Exchange must serve an international customer base.
- Exchange must provide a bid-offer spread for an immediate sale (offer) and an immediate purchase (bid).
- Minimum trade size must be less than 1,500 USD or equivalent.
- Daily trading volume must meet minimum acceptable levels as determined by CoinDesk.
- Exchange must represent at least 2% of the total 30-day cumulative volume for all of the exchanges included in the BPI.
- Banking transfers and/or bitcoin transfers in or out of the exchange must be completed within seven business days, if deposit and withdrawal methods are not offered for various countries and/or currencies.
Currently, these bitcoin exchanges meet the criteria and are therefore included in the BPI calculation:
How exactly is the BPI calculated?
The main features and criteria are as follows:
- The CoinDesk BPI is a simple average of leading XBT/USD exchange prices.
- The BPI is expressed as the midpoint of bid/ask spread.
- The BPI is updated every 60 seconds.
- If an exchange does not update its price for more than 30 minutes, it is omitted from the live BPI calculation until it is updated again.
- New index historical data commences on 1 July 2013.
- Prior index historical data is obtained via Mt. Gox.
- End-of-day high, low, and closing BPI is based on Greenwich Mean Time (GMT) or British Summer Time (BST) when appropriate.
- Non-USD BPI prices are implied based on rates obtained via openexchangerates.org.
- Any updates to the BPI criteria and formula shall occur monthly on the first day of the month, or more frequently if required.
Why is the BPI not volume-weighted?
The decision to apply a simple average, as opposed to a volume-weighted average, for the CoinDesk BPI was made because the bitcoin market currently lacks sufficient depth and regional liquidity.
Since trading volume now favors particular regions, a volume-weighted approach would not act as a proper global indicator, because each international bitcoin exchange is not equally available to all national trading participants.
A simple average does not favor a regional exchange with high volume and ensures that the BPI is meaningful for the largest number of market participants. Also, a simple average approach minimizes the impact of volume irregularities and accidentally excluding an exchange.
As overall liquidity improves and the number of global exchange choices increases, the impact of regional variances should diminish and a volume-weighted approach may become more appropriate.
CoinDesk Bitcoin Price Index API
For free access to BPI data, please take a look at our API information page.
BPI change log
10th Feb 2014 16:00:00 UTC: Mt. Gox was removed from the BPI for failing to meet its criteria.
10th Feb 2014 15:30:00 UTC: The sixth criterion for inclusion in the BPI was amended to include the option for bitcoin transfers to be completed within seven days in place of fiat transfers.
28th Nov 2013 12:00:00 UTC: Mt. Gox was added to the CoinDesk BPI due to a reduction in the risk premium and the option of additional deposit/withdrawal methods.
7th Nov 2013 00:00:00 UTC: CampBX was removed from the CoinDesk BPI due to sustained diminishing volume and a lack of regular 24-hour trading activity.
4th Nov 2013 12:00:00 UTC: The minimum acceptable volume criterion was amended so that each exchange must represent at least 2% of the total 30-day cumulative volume for all exchanges in the BPI.
20th Sep 2013 12:00:00 UTC: A criterion was added specifying that exchange daily trading volumes must meet minimum acceptable levels as determined by CoinDesk.
The CoinDesk Bitcoin Price Index is a composite price and not intended for use for investment purposes. Nothing published by CoinDesk constitutes an investment recommendation, nor should any data or written content published by CoinDesk be relied upon for any investment activities. CoinDesk strongly recommends that you perform your own independent research and/or speak with a qualified investment professional before making any financial decisions.