Source

When Tiger's speech causes a more dramatic volume impact than the FOMC you know this market is all sorts of perfectly efficient. Bloomberg's
chart of the day below shows the total NYSE volume change in-between
when Tiger started his convoluted and meandering mea culpa, and when he
ended.

Curiously (or not at all once you realize that algos now have a low volume trigger for activating buying programs), in the period when there was no trading volume, the market jumped, only to see the new
baseline level as of the end of his speech be today's resistance level.

In a Bloomberg TV interview Mark Crumpton notes:

“beginning around 11:00 a.m. New York time a trading decline during the time of that statement. Trading on all U.S. exchanges declined during Woods'
conference, falling to 456 million shares from an average of 576.8
million during the five previous 15-minute segments, data compiled by
Bloomberg shows. New York Stock Exchange trading fell to about 100,000
shares in the minute the speech began, the lowest of the day, then shot
above 600,000 when it ended, the highest for any period except just
after exchanges opened."

Of course, by the time traders came back to their desks, the fume-volume algo had already taken the market substantially higher to the new resistance level.