The downward trading movement of Cardinal Health's stock is likely due to the market's reaction to the updated FY24 EPS guidance, which may have been below investor expectations. The reiteration of long-term financial targets without an upward revision can also contribute to a lack of investor enthusiasm. However, the announcement of a share repurchase program is generally seen as a positive action, as it can indicate the company's confidence in its own stock and can lead to earnings per share accretion. The net impact is negative in the short term due to the guidance update, but the buyback program may provide some offsetting support.