(Adds comment from BNY Mellon, banking analyst) BOSTON/NEW YORK, Aug 27 (Reuters) - BNY Mellon Corp's computer snafu in calculating the prices of mutual funds and exchange-traded funds could extend into the weekend, prolonging confusion over the price of recent trades and any potential compensation owed. Some of the largest U.S. fund managers rely on BNY Mellon to calculate the net asset value (NAV) of their funds but a failed software upgrade last weekend buckled the system just as investors headed into a tumultuous week of trading sparked by fears about the Chinese economy. "BNY Mellon is the plumber to mutual funds and capital markets," said Mike Mayo, a banking analyst at CLSA. "There are a couple of broken pipes, but it doesn't seem like a systemwide issue ... It might not be evidence, but this is a reminder that BNY needs to further upgrade its technology platform." The breakdown affected 20 mutual fund companies and 26 ETF providers, BNY Mellon spokesman Kevin Heine said. He did not have any information on how many funds were... More