More than one-third of states have started implementing measures to control and reduce greenhouse gas emissions, primarily through the development of GHG emission inventories and regional cap and trade programs. Although most state-level initiatives focus on large-scale sources of GHG emissions, such as coal-fired electric plants, smaller ones may be subject to emission limitations or allowance purchase requirements. Congress has also considered passing laws to reduce greenhouse gas emissions. This type of climate change regulatory and legislative initiatives could have a significant negative impact on Greylock Productiona's business capital expenditures.