Sum Only Subset Records Included in Max Sale Date

I have the following query: The sum(taxcredit) is not working -- it is
summing all records by PED (period end date) where as I only want it to sum
the records associated with the sale date that equals Max(Sale_Date). How
can I do this?

SELECT TaxCredit.COMPANY_ID AS Co, TaxCredit.REPORT_DATE AS PED,
Max(TaxCredit.SALE_DATE) AS Sdate, Sum(TaxCredit.TaxCredit) AS TaxCredit
FROM TaxCredit
GROUP BY TaxCredit.COMPANY_ID, TaxCredit.REPORT_DATE
ORDER BY TaxCredit.COMPANY_ID, TaxCredit.REPORT_DATE;