On February 16, 2018, Coinbase admitted that some customers were overcharged in error for credit and debit purchases of cryptocurrencies. The problem was initiated when banks and card issuers changed the merchant category code (MCC) for cryptocurrency purchases earlier this month. This meant that cryptocurrency payments would now be processed as "cash advances", meaning that banks and credit card issuers could begin charging customers cash-advance fees for cryptocurrency purchases. Any customers who purchased cryptocurrency on their exchange between January 22 and February 11, 2018 could have been affected. At first, Visa blamed Coinbase, telling the Financial Times on February 16 that it had "not made any systems changes that would result in the duplicate transactions cardholders are reporting." However, the latest statement from Visa and Worldpay on the Coinbase blog clarifies: "This issue was not caused by Coinbase."
Bitcoin is the world’s first virtual digital currency underpinned by a completely decentralized blockchain technology also known as the Distributed Ledger Technology (DLT). Bitcoin was first created in 2009 by an anonymous identity of Satoshi Nakamoto. Bitcoin allows for peer-to-peer transactions and is completely free of any third-party involvement like financial institutions or central banks. The Bitcoin’s blockchain network maintains a history of all the transactions made and facilitates instant funds transfer with minimal transaction fees required to cover the cost of network operation. The total supply of Bitcoin is fixed at 21 million coins and its smallest fractional unit is called as Satoshi. Each Satoshi is a hundred millionth of a Bitcoin which means 100,000,000 Santoshi = 1 BTC. Bitcoins are generated by a process known as ‘mining’ which involves solving of complex mathematical algorithms. The miners involved in the mining process look after the Bitcoin network security and validate each transactions taking place on the network. Bitcoin can be exchanged with other digital currencies or fiat currencies. Bitcoin is used as a means of payment by over 100,000 vendors and merchants.
Bitcoin mining saps energy, costly, uses more power and also the reward delays. For mining, run software, get your wallet ready and be the first to solve a cryptographic problem and you get your reward after the new blocks have been added to the blockchain.Mining is said to be successful when all the transactions are recorded in the blockchain and the new blocks are added to the blockchain.
In April 2019, a UK corporate filing stated that Coinbase's non-U.S. revenue grew 20% to €153 million (U.S.$173 million) in 2018 resulting in a net profit of €6.6 million. Coinbase UK CEO Zeeshan Feroz said the company's non-U.S. operations accounted for nearly one-third of the company's overall revenue and Reuters estimated that the company's global revenue totaled "around $520 million" in 2018.