Are internal capital markets efficient?

Using segment information from Compustat, we find that the investment by a segment of a diversified firm depends on the cash flow of the firm's other segments, but significantly less than it depends on its own cash flow. The investment by segments of highly diversified firms is less sensitive to their cash flow than the investment of comparable single-segment firms. The sensitivity of a segment's investment to the cash flow of other segments does not depend on whether its investment opportunities are better than those of the firm's other segments.