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 may also consider passing laws to reduce greenhouse gas emissions, but these actions could have a significant adverse effect on Greylock Productiona's business capital expenditures and financial performance.