def _reindex_values(new_index, values, initial_value):
    """
    Conform values to new index

    Parameters
    ----------
    new_index : pandas.Index
    values : pandas.Series
    initial_value : float

    Returns
    -------
    pandas.Series
    """
    first_step = values.index[0]
    new_values = values.reindex(new_index, method="ffill")
    new_values.loc[new_values.index < first_step] = initial_value
    return new_values