Aligning U.S. Market Data with Japanese Stock Forecasts
Summary
The document explains how to align U.S. and Japanese market data when forecasting Japanese stock prices. Its central rule is to use only information available before the forecast target. Because the U.S. market closes while the next Japanese trading day has not yet begun, Wednesday’s S&P 500 close can be used alongside Wednesday’s Japanese close to predict Thursday’s Japanese open or close. This timing makes the U.S. close a valid predictor for the next Japanese session, even though the calendar dates match.
The discussion also asks how to handle dates without an S&P 500 observation and specifically raises Friday data, but the answer does not address those missing-date details. It offers no empirical test, predictive model, or performance evidence; it gives a timing example to clarify the information set. Actual alignment still depends on market holidays, daylight-saving shifts, the forecast cutoff, and whether the chosen U.S. observation was published before the Japanese target period.
Key ideas
- Use data known before the Japanese forecast period to avoid look-ahead bias.
- A U.S. market close can precede the next Japanese trading session, even when dates appear to match.
- Wednesday’s S&P 500 close may be considered when forecasting Thursday’s Japanese market.
- The document leaves missing U.S. observations and holiday alignment unresolved.
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# python: How use the S&P 500 index to predict japan stock,namely timezone issue # python: How use the S&P 500 index to predict japan stock,namely timezone issue I want to use American stock index, such as S&P 500 index(open, close...) to predict japan stock daily close price or other with machine learning. I found that there is timezone between japan and New York timezone, there are about 13 hours difference, I mean Wednesday, 5 July 2017, 19:12:00 in Tokyo time, the New York time is: Wednesday, 5 July 2017, 06:12:00. I mean if I want to use the S&P 500 index which is American index to predict japan stock daily close price, I think I can't use the same day(date) data of s&p 500 and japan stock data to predict the next day close price since there are time difference between Japan and USA. For example, if want to predict 7/6 Japan stock close price, I can use the 7/5 japan stock price data for features, and I can't use the 7/5 S&P 500 index data for features, I should use the 7/4 S&P 500 index data for predicting 7/6 stock price. I want to ask: (1). Should I use the yesterday or today data of S&P 500 data to predict tomorrow japan stock price. (2). How to processing the missing value of S&P 500 data which some date(I mean the same date of japan stock price) is missed. How about Friday S&P 500 index. Thanks! ## Answer by Alex C (score 1, accepted) https://quant.stackexchange.com/a/35009 To forecast something you can use any variable that is known before the result you are trying to forecast. For example the Wednesday close of S&P and the Wednesday close of Nikkei can be used to predict the Thursday Open and/or Thursday Close of Nikkei. When S&P closes on Wednesday it is about 5 am Thursday in Japan so the Thursday business activity in Japan has not begun (or finished) yet. So a prediction would be meaningful, it would be looking forward in time. In general you can use today closing index value of S&P 500 to predict tomorrow Japan stock price.
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