Daniel Gross hasn't a clue:

The conventional investing wisdom assumes that a deal – any deal – to avert the fiscal cliff will be good for stocks and the economy at large. That may be true. It may also not be true. In fact, I suspect that at the end of the day the people who are agitating most ardently for a big deal are going to be very disappointed. Compared with a few weeks ago, we are much less likely to have major entitlement reform and more likely to have large tax increases on the rich, with marginal rates rising, taxes on capital gains and dividends rising, and the rich losing some of their cherished deductions. The investor class has been begging for a resolution. The resolution they’re likely to get could be a sharp slap in the face.

Will that be good for stocks in 2013 and beyond? Who knows? In fact, hiking taxes significantly on investors may not influence the markets at all. My colleagues in the politico-financial industrial complex vastly, vastly overvalue the relation of government policy and marginal tax rates to asset prices in the stock market – especially my colleagues on the right side of the aisle.