Preprint
Sep 2026
Does Training on Future Data Pay? Look-Ahead Bias in Forecasting with Pretrained Models
We examine whether post-origin training information inflates the measured accuracy and economic value of financial forecasts. We evaluate five sets of financial time-series foundation models, each comprising independently trained annual vintages under U.S., global, and factor-augmented training environments, across 14...
Hai-Qiang Chen, Li Chen, Yun-Long Chen et al.
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