One investor who wasn’t deterred was Barstool Sports Inc. founder Dave Portnoy. In May, he announced to his 2.6 million followers on Twitter that he’d bought $40,000 worth, despite saying that SafeMoon could be a Ponzi scheme, a scam in which early investors’ returns are paid with funds coming from later buyers that collapses when new deposits dry up or too many people try to cash out.
Beyond the clampdown by some governments, what bitcoin really needed to achieve sustained success was overall mainstream acceptance. While some financial institutions announced projects exploring blockchain-based solutions, many others balked.

Before joining the OCC, Brooks worked as the chief legal officer for Coinbase, a major competitor to Binance.US.
In order to provide a methodology to detect bubbles in time series, Phillips, Wu, and Yu [23] proposed the supremum augmented Dickey-Fuller (SADF) test. This applies a series of right-tailed unit root tests to expanding windows of a time series (with a fixed start date), defined by where r2 is the final data point to be considered in each window, starting at r0 which is a fraction representing the smallest allowed window size and expanding to 1(the complete data set).