Washington (United States) (AFP) - Alan Greenspan, the longtime US Federal Reserve chief who presided over an unprecedented period of American economic expansion but was faulted for failing to rein in markets ahead of the 2008 global financial crisis, has died aged 100.

Greenspan guided the world’s biggest economy through a stock market crash in 1987 as he first took up his post, the Mexican and Asian financial crises, the dotcom boom and bust, and the September 11, 2001 attacks.

A native New Yorker who excelled at math as a child but initially studied music before pivoting to economics, Greenspan spent decades in the inner circles of power in Washington, ultimately leading the Fed for presidents of both political parties.

Greenspan was hailed by some as the greatest central banker the world has ever known, winning praise for his steady hand and cool demeanor.

Supporters admired his willingness to cut interest rates and keep them low even as unemployment rates fell, which conventional wisdom said would cause inflation to spiral out of control.

But his impenetrable prose – used to avoid committing to any particular course – and his confidence in unfettered markets and institutions to correct themselves frustrated critics, who believed the US economy needed stronger guardrails.

And after the world sank into crisis in 2008, soon after his retirement in 2006, his decision not to do anything to rein in the mortgage markets was viewed as naive.

Born on March 6, 1926, Greenspan grew up an only child raised mostly by his mother after she separated from his stockbroker father.

- Music first -

Initially, rather than going to college, he attended the elite Juilliard School to study music. After he was declared unfit to serve in the military due to a lung issue, he went on to play clarinet and saxophone in a band.

Greenspan earned $62 a week – more than his mother was making in her job at a department store, according to biographer Sebastian Mallaby, who wrote “The Man Who Knew: The Life and Times of Alan Greenspan” in 2016.

He read books on finance in his free time and helped his bandmates with their taxes.

In 1945, he quit music to attend New York University, where he would eventually earn a PhD in economics.

Greenspan started a consulting firm where he delved into economic and manufacturing data, a habit that would become the trademark – he was known for poring over statistics in his bathtub.

He became an active member of the libertarian salon surrounding anti-government writer and philosopher Ayn Rand.

His thinking evolved during his career, but he never fully relinquished his Randian support of laissez-faire economies free from government intervention.

Greenspan entered politics in the late 1960s as an adviser to Richard Nixon during his successful campaign for president, but initially declined to take a job in the Republican administration.

When he did accept the post of White House economic adviser, he was not confirmed until after Nixon resigned in disgrace, and working for Gerald Ford.

In 1987, another Republican president, Ronald Reagan, named Greenspan to serve as chair of the Federal Reserve.

It was a position he would hold until January 2006 serving under four presidents – Reagan, George H.W. Bush, his Democratic successor Bill Clinton and George W. Bush.

- Market turmoil -

Greenspan was tested early in his new post – on “Black Monday” in October 1987, the benchmark Dow Jones Industrial Average collapsed by nearly 23 percent – still the biggest single-day percentage drop in the index’s history – as part of a global market crash.

The new Fed chair issued a terse statement promising central bank support, and the Fed pumped liquidity into the financial system.

It worked. Rather than another Great Depression like the one that followed the 1929 crash, markets recovered quickly.

The world was nevertheless battered by a series of economic crises in the years that followed: Mexico (1994), Asia (1997) and Russia’s debt default (1998).

And then in a precursor to the global meltdown a decade later, Long-Term Capital Management (LTCM), which sold an unregulated financial instrument known as over-the-counter derivatives in 1998, was on the brink of collapsing and taking the financial system down with it.

Greenspan’s Fed lowered the benchmark interest rate three times, and it engineered a massive bailout for LTCM.

A few months later, Greenspan was featured on the cover of Time magazine with colleagues under the headline “The Committee to Save the World.”

But when the US housing market took off in the later 1990s and derivatives again were used to package mortgages to sell to investors – supposedly to dilute the risk – the Fed sat back.

Markets came to rely on the “Greenspan put” – a perceived guarantee the Fed would cut rates whenever they were in trouble. Those low rates spurred the mortgage market to dangerous heights before it all came crumbling down.

Alan Blinder, a Princeton economics professor who served as Fed vice chair, said Greenspan had a “legitimate claim to being the greatest central banker who ever lived.”

But with the financial crisis in the rear view mirror, he said Greenspan “really fell down on the job when it came to regulatory policy.”

His “excessive reliance on the self-regulating aspects of markets seemed dangerously naive, and eventually blew up in his face and everybody’s face,” Blinder told AFP.

Greenspan, who retired just before disaster struck, acknowledged to Congress in late 2008 that he had “made a mistake” in presuming companies were best positioned to protect themselves and their shareholders without government oversight.

He said he was “shocked” by the “flaw in the model” of economic behavior he had long relied on.