You're off-topic and completely non-responsive. The question of whether officers of a corporation have a fiduciary duty to maximize shareholder value is utterly orthogonal to the question of whether there can be local peaks and valleys in the chart of that value's growth.

Stopping operations, liquidating all the assets, and putting the whole mess in a savings account... that would eliminate local troughs, but is so obviously not in the shareholders' best interests that it might even violate the duty of good faith.