Ann: Update - Notification of buy-back - WHC, page-20

From the same website!
Sinking Dividends

At times companies can cut their dividends when they are spending money on share buybacks. That’s because the company will have less cash to hand out in quarterly dividends after share buybacks. Investors who rely on dividend checks for income will suffer the most.

Poor Predictions

Although companies can buy back their shares when the price is low, it doesn’t happen most times. Predicting the stock market can be tricky. Companies can buy back shares at their highest value, which makes the share repurchase a bad use of their capital.