While 2018 has been a difficult year for cryptocurrencies, some financial experts are still bullish about them. Among these experts is Aaron Brown, who was Chief Risk Manager for AQR Capital Management. He is also a prominent author of books about both risk management and gambling. In an op-ed Brown wrote for Bloomberg on December 20, he gave a surprisingly high grade to the way digital currencies performed in 2018, in spite of the steep decline of prices. He gave them a grade of B+ while comparing Bitcoin's 80% price drop to similar percentage declines in both 2011 and 2013. Brown further noted that this year's decline in Bitcoin's prices has actually been milder than its decline in 2011. Though he admitted that this year's decline was harsher than the decline in 2013. Brown stressed that, in 2011, Bitcoin's bottoming up occurred within a year of its high, but it was able to fully recover within two years. He further stressed that a similar pattern occurred in 2013, though this time it took 4 years before the digital currency fully recovered its losses. In his op-ed, Brown also noted the similarities between the 2018 cryptocurrency crash and the 2007 stock market crash. He says that both charts are similar if you look at them one year prior to their highs and one year afterward. Though Brown further says that a cryptocurrency recovery may take more than the 3 years it took for the stock market to recover after 2007. Brown further compared cryptocurrencies to the Nasdaq Composite Index. This index collapsed along with the dot-com bubble in 2000 and took 15 years to recover. Because of this, it would not surprise Brown if it takes many years for cryptocurrencies to recover what they lost this year. But he insists that "recoveries from crashes are common" and that he is confident that digital currencies will not disappear. He believes this largely because he believes in the technology behind them. Coinciding with Brown's op-ed, cryptocurrencies rose, with Bitcoin passing $4,000 for the first time since December 3. It rose 10% for the day and has risen 25% in the past week.