The Saudi Arabian stock market has been through a spectacular boom-bust cycle driven by a speculative frenzy over the boom in oil prices along with government sanctioned mass participation in the market:
In the past three years, up to nine million Saudis, or half the
population, have started playing the market in the conservative desert
state, whose strict brand of Islam outlaws standard forms of gambling.
They were encouraged by a government which hoped the bourse would
enable citizens to share in the economic boom that has come with a rise
in world oil prices not seen since the 1970s. It hoped that would help
to iron out some of the country's huge disparities of wealth.
This rosy scenario of shared wealth ended badly after the Saudi Arabian Capital Markets Authority ("CMA") engaged in a ham-handed attempt to regulate speculative excesses:
The March 14 plunge was a severe reaction by speculators when the
CMA decided to impose a daily price movement band of 10 percent.
The
April 11 crash was a response to the CMA suspending two dealers on
suspicions of market manipulation.
The lack of corporate transparency,
small-time and first-time investors’ ignorance of the fundamentals of
investments, and the long-term phenomenon of unmonitored margin lending
by banks were some of the other factors that aggravated the plunge.
The resulting 50% crash produced a pretty ugly looking chart for the Tadawul Market Index:

Market strategists have also theorized that the Saudi crash put pressure on the US markets:
A lot of the selling in the U.S. stock market over the past two weeks
was sparked by hedge funds invested in Saudi Arabia, said Jeffrey Saut,
market strategist for Raymond James & Associates in St. Petersburg.
He said the funds needed to raise cash, but their Saudi positions were
illiquid, so they sold U.S. stocks instead.
Saudi investors are understandably upset:
Saudis hit by a recent stock market
crash are resorting to car stickers to vent their anger at the
wealthy speculators who have been blamed for the decline. The English-language stickers reading "Big Thieves!" show a
stock market ticker and the names of some popular listed firms. [...]
The stock market crash, which affected more than 3.5 million middle
income investors, has delayed the marriages of many people this summer,
Asharq Al-Awsat newspaper reported. Every summer, tens of thousand of
Saudis get married but this year, the number is expected to drop by more than 50 percent.
Saudi King Abdullah has a surefire plan:
BBC: Saudi King Plans "Risk-Free Fund" - Saudi
Arabia's King Abdullah plans to set up a risk-free investment fund in a
bid to attract small investors to the country's flagging stock market.
Saudi
citizens will be able to invest up to 500,000 riyals ($133,000;
£70,600), in the bourse - buying and selling on the market for two
years. The individuals can keep any gains but the state will absorb losses.
King Abdullah did not give a starting date for the scheme - which could attract up to 3 million investors. However he said he was "determined" to implement it.
"The fund will be for people of limited income, employees and others...this group matter most to me," he said. "If
they win then this is their luck, with God's will, and if they lose,
then their capital is preserved with us," the monarch said.
Ah, it's nice to know oil dollars go to such productive uses.
The BBC was kind enough to also note that the mass disruption of a
market crash could increase the possibility of repercussions both
within and beyond Saudi borders:
"Poverty and unemployment affect terrorism and
instability and the king knows the result of this decision, which has
important political significance"
I
find this all very interesting, and it's suprising how little coverage
this got in the US press - so much for those "efficient markets for
information" that the internet is supposed to create. - Ed