If you've simplified your business by outsourcing some supply chain tasks, you're in good company. A full two-thirds of Fortune 500 companies now use third-party logistics service providers (3PLs) for logistics and supply chain functions, according to a new report from market research and consulting company Armstrong & Associates.

The annual Armstrong research report, titled "Trends in 3PL/Customer Relationships," draws on information from the company's proprietary database, which includes data on 2,864 3PL/customer relationships. The study provides detailed information on the top outsourcers, service demand and market size by industry segment.

According to the report, the biggest outsourcers are General Motors,Wal-Mart, DaimlerChrysler, and Ford Motor Co., each of which uses 30 or more 3PLs. It pegs the global Fortune 500 3PL market at $158.1 billion for 2005, with automotive 3PL customers alone spending an estimated $35.8 billion with 3PLs. As for the most commonly outsourced activities, they are transportation management (20.5 percent), warehousing (19.3 percent) and value-added services (18.5 percent).

The complete report is available from Armstrong & Associates online at www.3PLogistics.com.