Sept. 5 (Bloomberg) -- ``The Dark Knight,'' the latest chapter in the Batman film saga, took 30 days to become No. 2 in U.S. box office history. It joined the other top-four earners, ``Titanic,'' ``Star Wars'' and ``Shrek 2,'' by also debuting as the Standard & Poor's 500 Index rose.

Time Warner Inc.'s film earned $471.5 million in the month starting July 18, while the S&P 500 rose 3 percent. Eight of the top 10 movies, including three ``Star Wars'' episodes, have opened as the benchmark stock index rose for a 30-day period, according to data compiled by Bloomberg and box office tracker Media By Numbers LLC.

``E.T. the Extra-Terrestrial'' and ``Spider-Man'' were the only blockbusters released as the market fell.

The CHART OF THE DAY shows the performance of the S&P 500 in the first 30 calendar days of the five biggest-selling films. In the 31 years since Luke Skywalker first brandished a lightsaber, the S&P 500 has risen 61 percent of the time on a monthly basis, the data show.

``It might be a stretch to say there's a direct relationship with the overall market,'' said Paul Dergarabedian, president of Media By Numbers. ``But there is certainly a ripple effect on other economic commodities when movies do well.''

Earnings for ``Dark Knight'' in the U.S. and Canada reached $504.7 million on Sept. 1, trailing only ``Titanic's'' $600.8 million. Movies on average generate 24 percent of domestic box office sales in the first weekend, according to Amit Joshi, assistant professor of marketing at the University of Central Florida.

To contact the reporter on this story: Lee J. Miller in Bangkok at lmiller@bloomberg.net

Last Updated: September 4, 2008 22:35 EDT