  We investigate possible origins of trends using a deterministic threshold
model, where we refer to long-term variabilities of price changes (price
movements) in financial markets as trends. From the investigation we find two
phenomena. One is that the trend of monotonic increase and decrease can be
generated by dealers' minuscule change in mood, which corresponds to the
possible fundamentals. The other is that the emergence of trends is all but
inevitable in the realistic situation because of the fact that dealers cannot
always obtain accurate information about deals, even if there is no influence
from fundamentals and technical analyses.
