Over 33% of states have initiated measures to limit greenhouse gas emissions, primarily through the development of GHG emission inventories and regional cap and trade programs. While 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 initiatives could have a significant adverse effect on Greylock Productiona's business capital expenditures and financial results.