Introduction
Complex movements in stock market prices affect the personal fortunes of people around the
globe [1–5]. An ability to more accurately quantify and predict such changes would allow us to
gain more insights into how financial crises arise [6] and provide greater empirical basis for the
development of theories of financial market behavior [7–13].
The financial markets were however one of the earliest sources of large scale datesets on
human behaviour, where such data have recently become the focus of the new field of computational
social science [14–24]. A vast amount of data on financial decisions made in stock
markets is therefore available [25–29]. Previous studies have shown that distributions of
returns observed in empirical data are consistent with power law decay [30–42], in contrast
with widely used models that assume Gaussian behavior of these returns. Power law behavior
has also been observed in other economical and financial sectors of society [43, 44].
Changes in stock market prices can occur at a range of different time scales. Here, we analyze
a large dataset of stocks forming the Dow Jones Industrial Average (DJIA) at a second-bysecond
resolution for a range of different time scales in order to quantify the distribution of
returns. We provide evidence that while the distribution of returns exhibits power law behavior