It isn't just the earnings number that JP Morgan Chase reports that matters. It is how the bank gets there.

All eyes will be on JP Morgan when it announces second-quarter results on Friday and, crucially, provides a fuller account of the trading loss that has engulfed the bank. The first question will be just how big a loss will be left in the wake of a trader who became known as the "London Whale." Markets expect about $4bn to $5bn. The next is what levers JP Morgan might pull to offset the loss and what that says about the quality of its earnings.