InTheLoop, you don’t need to assume that the y intercept is unknown. The natural model assumes that the price of BTC was 0 at Genesis Block so the regression model fitted to the log of the prices and log of time gives you both A and alpha, log10(price)=A+log10 (time in days from Genesis Block). A as derived from the fitting is so small to be considered basically 0, as it should be if the value of BTC was zero when it was created. I even found few transactions that were outside the market (before market existed) and even these early transactions fit the model incredibly well.