BASIC QUESTION - SQL SERVER

Hello
    I have a table of accounting entries,
    For different companies.

    The number of accounting records could not be self incremental
    (Each company has its own numbering)

    Even the numbered accounts is reorganized at the end
    The accounting period

    How can I get the largest number of accounting records
    Home after add records?

    In Mysql there is a command "MAX (number) FOR UPDATE"
    Blocking the table until commit

    What is the most efficient in SQL server?

Jorge Accinelli