Coinbase shares slumped 11 per cent before the bell and are set to open at their lowest in a month on Friday, after the crypto exchange reported a drop in second-quarter adjusted profit due to a slowdown in trading. The stock was last trading at $335.33, on track to wipe out nearly $11 billion of market value if current levels hold. It has gained 52 per cent this year as of last close, ranking among the top 15 gainers in the benchmark S&P 500 index, which Coinbase joined in May. "We see the