Work in progress (WIP), also called work in process, is inventory that has begun the manufacturing process and is no longer included in raw materials inventory, but is not yet a completed product. On a balance sheet, work in progress is considered to be an asset because money has been spent towards a completed product. Because the product has not been completed, however, WIP is valued lower.
Lean production principles consider excess WIP to be an indicator of waste caused by bottlenecks in the manufacturing process or an unstable supply chain. Too much work in progress is undesirable because it ties up money that could be generating higher returns somewhere else in the company.
See also: enterprise asset management