Variation % calculation based on start

Hi fosterXO ,

According to your description, here's my solution.

Create two measures.

Price1 Measure =
VAR _Start =
    MAXX (
        FILTER (
            ALLSELECTED ( 'Table' ),
            'Table'[Date] = MINX ( ALLSELECTED ( 'Table'[Date] ), 'Table'[Date] )
        ),
        'Table'[Price 1]
    )
RETURN
    DIVIDE ( MAX ( 'Table'[Price 1] ) - _Start, _Start )

Price2 Measure =
VAR _Start =
    MAXX (
        FILTER (
            ALLSELECTED ( 'Table' ),
            'Table'[Date] = MINX ( ALLSELECTED ( 'Table'[Date] ), 'Table'[Date] )
        ),
        'Table'[Price 2]
    )
RETURN
    DIVIDE ( MAX ( 'Table'[Price 2] ) - _Start, _Start )

Get the correct result:

I attach the file below for your reference.

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Best regards,

Community Support Team_yanjiang