They are standard rates for contracting and outsourcing firms. 500 euro a day is about 100k a year, accounting for 200 work days in a year. Remove the margin

They are standard rates for contracting and outsourcing firms. 500 euro a day is about 100k a year, accounting for 200 work days in a year. Remove the margin of the firm, pension, healthcare, sick leave, company taxes, office costs, benefits... and what's left is the gross salary.