If mean reversion is truly an immutable law of investing, then investors might want to consider shorting the S&P 500 and going long Japan’s Nikkei index, DoubleLine CEO Jeffrey Gundlach remarked yesterday. The reason is simple math.

Since 1979, the S&P has appreciated 18-fold while the Nikkei is up fourfold. Move ahead 10 years and since 1989, the S&P is up sixfold while the Nikkei is down about 50%. Get the picture? In general, he warned clients not to expect the stability of financial markets in 2012 to “endure in 2013,” the year of the snake in the Chinese calendar.

Gundlach, who last year remarked that a major problem with U.S. fiscal policy over the last 30 years was that we cut taxes and “gave it to the rich guys,” also sounded off on the flip side of income polarization—tax polarization. Under the new federal income tax structure, 0.7% of the U.S. population will pay 40% of federal income taxes.

In his home state of California, the imbalance is even more absurd. The wealthiest Californians are getting a 25% hike in taxes, with the brunt of those tax hikes falling on just 4,000 people. If just 1,000 of them decide to leave the state, the tax increase will be a revenue-losing proposition for the state. Asked if DoubleLine plans to remain in California, Gundlach said “that’s the plan,” but hinted that the “snakes in Sacramento” might yet convince him otherwise.

Regarding financial markets, he noted that many stock markets around the world currently are overbought. He said that the Shanghai and Nikkei represent significantly better values than other developed markets. Within Japan itself, the best trade could be to go long stocks and short the yen, an overvalued currency.

Gundlach also reiterated his prediction that shares of Apple would fall to $425 in 2013. If the shares go nowhere for the next 30 days, Apple shares will have been flat for a full year. At some point, the appeal of successive generations of  iPhones will diminish.

Complacency in many sovereign debt markets makes them risky, unattractive investment options. All the yields on 10-year government bonds in various Eurozone nations—Spain (5.23%), Ireland (5.61%), Italy (4.44%), France (1.87%) and Germany (1.31%)—offer no upside and lots of potential downside. Ditto for high-yield and emerging market debt, where the underlying bond prices are likely to hold up only because the planet is starved for yield.

Gundlach expressed a degree of indifference to gold but added that if the precious metal breaks out to the upside, “you’ll do really well in silver,” which always behaves in a more manic manner than its higher profile sister.

Imbalances in the developed world are unsustainable, creating uncertain conditions that are unlikely to produce stability. Gundlach pointed to the 2001 projection by the Congressional Budget Office that the federal government would run a $5.6 trillion surplus over the next decade. Their number was close, but we got a minus sign instead, with a $6.2 trillion deficit.

The CBO failed to predict the events of September 11, two wars, Medicare Part D, or a bunch of bailouts, which combined cost an estimated $4.3 trillion. They didn’t even forecast a single recession. We got two, one of them nasty, that added another $3.3 trillion to the national debt. So take predictions with a grain of salt, particularly about the future.