Market Regulation Services - Trading Halt - Sierra Vista Energy Ltd - SVR.A SVR.B

May 21, 2008

    VANCOUVER, May 21 /CNW/ - The following issues have been halted by Market
Regulation Services (RS):

    Issuer Name: Sierra Vista Energy Ltd
    TSX-V Ticker Symbol: SVR.A SVR.B
    Time of Halt: 9:10 EDT
    Reason for Halt: Pending News

For further information:

For further information: contact - RS Inquiries (416) 646-7299 - *
Please note that RS is not able to provide any additional information
regarding a specific trading halt. Information is limited to general enquiries