Shares of ABX Air ( ABXA) plummeted 23% in late trading Thursday after the air cargo transport company said DHL, a major customer, plans to reduce the amount of services it receives from ABX. Among the changes, DHL will take over the truck line-haul network ABX manages, and DHL won't need ABX to manage its Allentown, Pa., hub. ABX estimates the line-haul and Allentown services comprised $292.3 million of its $1.46 billion in revenue for 2005. Separately, ABX Air said its fourth-quarter profit fell to $9.1 million, or 16 cents a share, from $18.1 million, or 31 cents a share, a year earlier. Revenue rose to $396.6 million from $361.4 million a year ago. Two analysts polled by Thomson First Call had an average estimate for earnings of 27 cents a share, while one analyst projected revenue of $429.9 million. Shares fell $1.86 to $6.15 in after-hours trading. Petco ( PETC) shares rose after the pet-supply retailer posted better-than-expected fourth-quarter results and announced a $100 million share buyback plan. The company's profit rose slightly to $26.8 million, or 46 cents a share, from $26.3 million, or 45 cents a share. Sales grew 10% to $541.5 million from $492.3 million, while same-store sales rose 2%. The results beat analysts' average estimates for earnings of 45 cents a share and sales of $536.8 million. Looking ahead, Petco forecast first-quarter earnings of 23 cents to 25 cents a share, excluding stock-options costs. Analysts forecast earnings of 29 cents a share. The company sees same-store sales growth of about 1% to 3% in the quarter. For the full year, the company sees earnings of $1.48 to $1.52 a share, before roughly 16 cents in options costs, with 2% to 4% same-store sales growth. Wall Street expects earnings of $1.35 a share. Petco shares gained 66 cents, or 3%, to $21.92 after hours.