As President Barack Obama widened his lead over Mitt Romney in polls this month, traders at hedge funds and investment firms began shooting emails to clients with a similar theme: It's time to start preparing for an Obama victory.

What many in the market worry about isn't that high earners may pay more in taxes if Obama is re-elected. It's gridlock in Washington come January, when more than $600 billion in spending cuts and tax hikes could kick in just as the country smacks into its borrowing limit again.

There is reason to expect a deal. If Obama wins, the Republican fight to make him a one-term president will be lost. With the elections over, there will be little reason or room for political posturing. House Republicans could finally decide to be more cooperative.

"They'll be faced with determining whether we get a recession or not," says Jeff Kleintop, chief market strategist at LPL Financial.

But investors remember the budget battle in the summer of last year, which ended with the country losing its top credit rating and panicked investors fleeing the stock market. Investors are fearful of a repeat. In a second term, Obama would likely again be pitted against a Republican-controlled House of Representatives.

"If you have any kind of gridlock, you run the risk of inaction," says Tom Simons, a market economist at the investment bank Jefferies. "This is a situation where inaction is the worst outcome."

The next fight could get just as messy, but most on Wall Street think Congress and Obama would eventually manage to postpone some of the $600-billion-plus "fiscal cliff" before the year is out and avoid tipping the economy into a recession.

The Congressional Budget Office recently laid out the grim consequences of dropping off the fiscal cliff. Starting Jan. 1, tax cuts signed by President George W. Bush expire as do Obama's cuts to payroll taxes. Federal spending on defense and other domestic programs will drop, while emergency unemployment benefits run out.

The combined effect off all these changes would shrink the economy nearly 3 percent at an annual rate in the first half of next year, the CBO estimates, and push unemployment up to 9.1 percent by the fall. Recent surveys of businesses suggest the threat is already weighing on the minds of executives when they're making hiring and spending plans.

For the world's biggest money managers, the fiscal cliff now ranks as the greatest hazard to the global economy, according to Bank of America's most recent fund manager survey. It topped the European debt crisis, a collapse in Chinese real estate and even a war between Israel and Iran.

The danger looms so large to most investors that they believe Washington will find a way to escape it.

"Ultimately, I think a deal gets done, but it's just a question of how long it takes to get there," Kleintop says. "By no means is it going to be an easy process. Gridlock means there's a greater chance that this drags on into next year."

Analysts at investment firms have kept a close eye on polling numbers and especially on the Intrade, an online marketplace where members can trade predictions on events like elections. Polls show voters leaning toward Obama in key swing states. On Intrade, the odds have swung strongly in Obama's direction, jumping to a 76 percent chance of re-election, up from 51 percent at the start of September.

Democrats are far less likely to take the House from Republicans, who hold a 50-seat majority. Intrade markets put the chance that Republicans will control the House at 74 percent.

If these forecasts prove right, the balance of power in Washington would remain the same. Democrats keep the White House and a slim majority in the Senate, and Republicans keep the House.