A Grayscale report found that Bitcoin returned about 225% over the past three years, but the gains were highly concentrated in a handful of trading days. Excluding the 5 best days would reduce returns to 95%; excluding 10 days would bring them down to 27%; and excluding 15 days would result in a loss of 11%. By comparison, the Nasdaq index returned 109% over the same period, with gains that were less concentrated. Grayscale believes that for a highly volatile asset like Bitcoin, not investing also carries an opportunity cost. Since the best trading days are difficult to predict, long-term investors should avoid market timing and maintain continuous exposure.