Flash PMIs land on Wednesday 23 September. Do you trade the flash reading or wait for the final figures?

S&P Global's release calendar lists the September flash PMIs for Wednesday 23 September. The eurozone reading is due at 08:00 UTC, the UK's at 08:30 UTC and the US reading at 13:45 UTC (9:45 a.m. Eastern Time). Japan's flash comes a day later, on Thursday 24 September, with Wednesday a public holiday there.

Three things are worth knowing about how a flash reading is built. It is calculated from around 80–90% of the survey responses that the final figure uses, and for the US composite the average difference between flash and final has been 0.1 points, with an average absolute difference of 0.4. In August the flash US composite index was 56.0, the eurozone's 52.1 and the UK's 52.5, and the US and eurozone readings were the highest in 52 and nine months respectively.

Since the flash is the first look and the final can shift slightly, traders handle it differently. PMIs explained covers the basics of what the index measures.

• Do you trade the flash reading, wait for the final, or ignore both and watch other data?
• How big a move from the previous month, or from the forecast, makes you act?
• Do you look at the composite, or at the services and manufacturing breakdown?
• How do you handle three releases in one morning and afternoon, at 08:00, 08:30 and 13:45 UTC?

Please share your own approach and reasoning. Posts that promise a direction or sell signals will be removed.