So where were the quants?
That’s what has been running through my head as I watch some of the oldest and seemingly best-run firms on Wall Street implode because of what turned out to be really bad bets on mortgage securities.
Before I started covering the Internet in 1997, I spent 13 years covering trading and finance. I covered my share of trading disasters from junk bonds, mortgage securities and the financial blank canvas known as derivatives. And I got to know bunch of quantitative analysts (”quants”): mathematicians, computer scientists and economists who were working on Wall Street to develop the art and science of risk management.
They were developing systems that would comb through all of a firm’s positions, analyze everything that might go wrong and estimate how much it might lose on a really bad day.
We’ve had some bad days lately, and it turns out Bear Stearns, Lehman Brothers and maybe some others bet far too much. Their quants didn’t save them.
I called some old timers in the risk-management world to see what went wrong.
I fully expected them to tell me that the problem was that the alarms were blaring and red lights were flashing on the risk machines and greedy Wall Street bosses ignored the warnings to keep the profits flowing.
Ultimately, the people who ran the firms must take responsibility, but it wasn’t quite that simple.
In fact, most Wall Street computer models radically underestimated the risk of the complex mortgage securities, they said. That is partly because the level of financial distress is “the equivalent of the 100-year flood,” in the words of Leslie Rahl, the president of Capital Market Risk Advisors, a consulting firm.
But she and others say there is more to it: The people who ran the financial firms chose to program their risk-management systems with overly optimistic assumptions and to feed them oversimplified data. This kept them from sounding the alarm early enough.
Top bankers couldn’t simply ignore the computer models, because after the last round of big financial losses, regulators now require them to monitor their risk positions. Indeed, if the models say a firm’s risk has increased, the firm must either reduce its bets or set aside more capital as a cushion in case things go wrong.
In other words, the computer is supposed to monitor the temperature of the party and drain the punch bowl as things get hot. And just as drunken revelers may want to put the thermostat in the freezer, Wall Street executives had lots of incentives to make sure their risk systems didn’t see much risk.
“There was a willful designing of the systems to measure the risks in a certain way that would not necessarily pick up all the right risks,” said Gregg Berman, the co-head of the risk-management group at RiskMetrics, a software company spun out of JPMorgan. “They wanted to keep their capital base as stable as possible so that the limits they imposed on their trading desks and portfolio managers would be stable.”