On a monthly basis, the collection system for FDI is based mainly on a combination of bank reports on settlement operations and direct communication of external transactions by resident enterprises (which on an annual basis have an external turnover exceeding EUR 100 000). For the valuation at market prices, additional information is collected from the Portuguese Stock Exchange (for inward investment) and from commercial data providers (for outward investment). For real estate we collect information from the Portuguese Authorities (please see question 15). In addition to these sources, FDI statistics are revised annually based on replies to IES survey (please see question 24).