MarkWest Energy Partners, LP (MWE)

Our profitability is affected by the volatility of NGL product and natural gas prices.

        We are subject to significant risks associated with frequent and often substantial fluctuations in commodity prices. In the past, the prices of natural gas and NGLs have been volatile, and we expect this volatility to continue. The New York Mercantile Exchange ("NYMEX") daily settlement price of natural gas for the prompt month contract in 2005 ranged from a high of $15.38 per MMBtu to a low of $5.79 per MMBtu. In 2006, the same index ranged from a high of $10.63 per MMBtu to a low of $4.20 per MMBtu. In 2007, the same index ranged from a high of $8.64 per MMBtu to a low of $5.38 per MMBtu. A composite of the weighted monthly average NGLs price at our Appalachian facilities based on our average NGLs composition in 2005 ranged from a high of approximately $1.31 per gallon to a low of $0.79 per gallon. In 2006, the same composite ranged from approximately $1.29 per gallon to approximately $0.99 per gallon. In 2007, the same composite ranged from approximately $1.76 per gallon to approximately $0.96 per gallon. The markets and prices for natural gas and NGLs depend upon factors beyond our control. These factors include demand for oil, natural gas and NGLs, which fluctuate with changes in market and economic conditions and other factors, including:

•

the level of domestic oil, natural gas and NGL production;



•

demand for natural gas and NGL products in localized markets;



•

imports of crude oil, natural gas and NGLs;



•

seasonality;



•

the condition of the U.S. economy;



•

political conditions in other oil-producing and natural gas-producing countries; and



•

government regulation, legislation and policies.

        Our net operating margins under various types of commodity-based contracts are directly affected by changes in NGL product prices and natural gas prices, and thus are more sensitive to volatility in commodity prices than our fee-based contracts. Additionally, our purchase and resale of gas in the ordinary course of business exposes us to significant risk of volatility in gas prices due to the potential difference in the time of the purchases and sales, and the potential existence of a difference in the gas price associated with each transaction.

Our profitability is affected by the volatility of NGL product and natural gas prices.

        We are subject to significant risks associated with frequent and often substantial fluctuations in commodity prices. In the past, the prices of natural gas and
NGLs have been volatile, and we expect this volatility to continue. The New York Mercantile Exchange ("NYMEX") daily settlement price of natural gas for the prompt month contract in 2005 ranged from a
high of $15.38 per MMBtu to a low of $5.79 per MMBtu. In 2006, the same index ranged from a high of $10.63 per MMBtu to a low of $4.20 per MMBtu. In 2007, the same index ranged from a high of $8.64
per MMBtu to a low of $5.38 per MMBtu. A composite of the weighted monthly average NGLs price at our Appalachian facilities
based on our average NGLs composition in 2005 ranged from a high of approximately $1.31 per gallon to a low of $0.79 per gallon. In 2006, the same composite ranged from approximately $1.29 per gallon
to approximately $0.99 per gallon. In 2007, the same composite ranged from approximately $1.76 per gallon to approximately $0.96 per gallon. The markets and prices for natural gas and NGLs depend upon
factors beyond our control. These factors include demand for oil, natural gas and NGLs, which fluctuate with changes in market and economic conditions and other factors, including:

•

the
level of domestic oil, natural gas and NGL production;




•

demand
for natural gas and NGL products in localized markets;




•

imports
of crude oil, natural gas and NGLs;




•

seasonality;




•

the
condition of the U.S. economy;




•

political
conditions in other oil-producing and natural gas-producing countries; and




•

government
regulation, legislation and policies.

        Our
net operating margins under various types of commodity-based contracts are directly affected by changes in NGL product prices and natural gas prices, and thus are more sensitive to
volatility in commodity prices than our fee-based contracts. Additionally, our purchase and resale of gas in the ordinary course of business exposes us to significant risk of volatility in
gas prices due to the potential difference in the time of the purchases and sales, and the potential existence of a difference in the gas price associated with each transaction.

Our profitability is affected by the volatility of NGL product and natural gas prices.

        We are subject to significant risks associated with frequent and often substantial fluctuations in commodity prices. In the past, the prices of natural gas and NGLs have been volatile, and we expect this volatility to continue. The NYMEX daily settlement price of natural gas for the prompt month contract in 2005 ranged from a high of $15.38 per MMBtu to a low of $5.79 per MMBtu in 2005. In 2006, the same index ranged from a high of $12.48 per MMBtu to a low of $4.20 per MMBtu. A composite of the weighted monthly average NGLs price at our Appalachian facilities based on our average NGLs composition in 2005 ranged from a high of approximately $1.25 per gallon to a low of $0.83 per gallon. In 2006, the same composite ranged from approximately $1.27 per gallon to approximately $1.03 per gallon. The markets and prices for natural gas and NGLs depend upon factors beyond our control. These factors include demand for oil, natural gas and NGLs, which fluctuate with changes in market and economic conditions and other factors, including:

•

the level of domestic oil, natural gas and NGL production;



•

demand for natural gas and NGL products in localized markets;



•

imports of crude oil, natural gas and NGLs;



•

seasonality;



•

the condition of the U.S. economy;



•

political conditions in other oil-producing and natural gas-producing countries; and



•

domestic government regulation, legislation and policies.

        Our net operating margins under various types of commodity-based contracts are directly affected by changes in NGL product prices and natural gas prices, thus are more sensitive to volatility in commodity prices than our fee-based contracts. Additionally, our purchase and resale of gas in the ordinary course of business exposes us to significant risk of volatility in gas prices due to the potential difference in the time of the purchases and sales, and the potential existence of a difference in the gas price associated with each transaction.

Our profitability is affected by the volatility of NGL product and natural gas prices.

We are subject to significant risks associated with frequent and often substantial fluctuations in commodity prices. In the past, the prices of natural gas and NGLs have been volatile, and we expect this volatility to continue. The NYMEX daily

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settlement price of natural gas for the prompt month contract in 2005 ranged from a high of $15.38 per MMBtu to a low of $5.79 per MMBtu in 2005. In 2006, the same index ranged from a high of $12.48 per MMBtu to a low of $4.20 per MMBtu. A composite of the weighted monthly average NGLs price at our Appalachian facilities based on our average NGLs composition in 2005 ranged from a high of approximately $1.25 per gallon to a low of $0.83 per gallon. In 2006, the same composite ranged from approximately $1.27 per gallon to approximately $1.03 per gallon. The markets and prices for natural gas and NGLs depend upon factors beyond our control. These factors include demand for oil, natural gas and NGLs, which fluctuate with changes in market and economic conditions and other factors, including:

·              the level of domestic oil, natural gas and NGL production;

·              demand for natural gas and NGL products in localized markets;

·              imports of crude oil, natural gas and NGLs;

·              seasonality;

·              the condition of the U.S. economy;

·              political conditions in other oil-producing and natural gas-producing countries; and

·              domestic government regulation, legislation and policies.

Our net operating margins under various types of commodity-based contracts are directly affected by changes in NGL product prices and natural gas prices, thus are more sensitive to volatility in commodity prices than our fee-based contracts. Additionally, our purchase and resale of gas in the ordinary course of business exposes us to significant risk of volatility in gas prices due to the potential difference in the time of the purchases and sales, and the potential existence of a difference in the gas price associated with each transaction.

Our profitability is affected by the volatility of NGL product and natural gas prices.

Changes in the prices of NGL products have historically correlated closely with changes in the price of crude oil.  Crude oil, NGL products and natural gas prices have been volatile in recent years in response to relatively minor changes in the supply and demand for NGL products and natural gas, market uncertainty, and a variety of additional factors that are beyond our control, including:

•              the level of domestic oil, natural gas and NGL production;

•              demand for natural gas and NGL products in localized markets;

•              imports of crude oil, natural gas and NGLs;

•              seasonality;

•              the condition of the U.S. economy;

18

Our profitability is affected by the volatility of NGL product and natural gas prices.

Changes in the prices of NGL products have historically correlated closely with changes in the price of crude oil.  Crude oil, NGL products and natural gas prices have been volatile in recent years in response to relatively minor changes in the supply and demand for NGL products and natural gas, market uncertainty, and a variety of additional factors that are beyond our control, including:

•              the level of domestic oil, natural gas and NGL production;

•              demand for natural gas and NGL products in localized markets;

•              imports of crude oil, natural gas and NGLs;

•              seasonality;

•              the condition of the U.S. economy;

18

Our profitability is affected by the volatility of NGL product and natural gas prices.

The profitability of our natural gas processing and NGL fractionation operations is affected by volatility in prevailing NGL product and natural gas prices.  Changes in the prices of NGL products have historically correlated closely with changes in the price of crude oil.  Crude oil, NGL product and natural gas prices have been subject to significant volatility in recent years in response to relatively minor changes in the supply and demand for NGL products and natural gas, market uncertainty and a variety of additional factors that are beyond our control, including:

•              the level of domestic oil, natural gas and NGL production;

•              imports of crude oil, natural gas and NGLs;

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