Sixteen of the nation's largest financial services firms warned President Barack Obama and Congress in a letter Thursday that interest rates could spike significantly if they do not come to an agreement to stop the series of automatic tax hikes and spending cuts known as the “fiscal cliff.”

Goldman Sachs chief executive Lloyd Blankfein, JPMorgan Chase chief Jamie Dimon, Bank of America chief Brian Moynihan and 13 other top executives signed on to a letter demanding prompt action. Without it, they warned, the economy could be hit hard and the United States could suffer a second debt ratings downgrade.

“Another downgrade of our nation's debt by a major rating service . . . could lead to significantly higher interest rates,” the letter says. “Higher interest payments would worsen our nation's fiscal burden and likely increase the uncertainty and instability in global financial markets.”

The letter, organized by the trade group the Financial Services Forum, comes as the White House and congressional Republicans appear prepared to play a game of chicken over the “fiscal cliff.” Obama officials say the president is prepared to veto any proposal to stop the “fiscal cliff” that does not increase tax rates on the wealthy, a red line that Republicans do not want to cross.

The letter is the latest sign that Wall Street, and corporate America more broadly, is planning to exert more pressure on lawmakers and the White House to come to agreement than it did last summer, when executives largely sat out the debt-limit debate.

Executives are also contributing millions of dollars to a campaign being waged by the Committee for a Responsible Federal Budget, a group working to promote a deficit reduction plan that shares a framework with the Simpson-Bowles plan.

If no agreement is reached, taxes on all Americans will increase significantly on Jan. 1, and the government will begin deep cuts to domestic and defense spending. Many economists predict the actions will push the economy at least into a short recession.

Credit-rating firm Standard & Poor's downgraded the U.S. AAA rating in August of 2011. Moody's has warned it might follow suit if an agreement cannot be reached — both to avert the fiscal cliff and put in place a long-term deficit reduction plan.