Sectoral search volumes and stock market movement.

<p>For each sector of the companies contained in the Standard and Poor´s 100 the development of closing prices <i>p</i>(<i>t</i>) of the index is drawn as a function of time for the first day of every week in the period between 4 January, 2004 and 4 January, 2014. Each index curve is dyed by a color code corresponding to the average change of search volumes for the respective companies of each sector <i>S</i>. The average change for each week over all company search queries for sector <i>S</i> is given by </p><p></p><p></p><p><mo>〈</mo><mo>Δ</mo></p><p><mi>n</mi><mi>S</mi></p><mo>〉</mo><p><mo>(</mo></p><p><mi>t</mi><mo>,</mo> <mo>Δ</mo><mi>t</mi></p><mo>)</mo><p></p><mo>=</mo><p></p><p><mo>∑</mo><mi>i</mi><mi>s</mi></p><p><mo>Δ</mo></p><p><mi>n</mi><mi>i</mi></p><p><mo>(</mo></p><p><mi>t</mi><mo>,</mo> <mo>Δ</mo><mi>t</mi></p><mo>)</mo><p></p><mo>/</mo><mi>S</mi><p></p><p></p><p></p><p></p><p></p>, with Δ<i>t</i> being 3 weeks.<p>