Negotiators are meeting every day at the White House until they reach a debt ceiling deal.
NEW YORK (CNNMoney) -- The public pressure on lawmakers to raise the debt ceiling was ratcheted up Wednesday when a major rating agency said it would put the sterling bond rating of the United States on review for possible downgrade.
Moody's Investors Services said it had initiated the review because of "the rising possibility" that Congress will fail to raise the debt ceiling by Aug. 2 -- something that could lead to a U.S. default on its debt.
If the debt ceiling isn't raised by then, the Treasury Department says it will no longer be able to pay all the country's bills in full and on time without being allowed to borrow new money. (Read: Debt ceiling FAQ)
"Moody's considers the probability of a default on interest payments to be low but no longer to be de minimis," Moody's said in a statement.
The United States enjoys its AAA rating in part for having always stood behind its debt and paid its bills on time. As a result, U.S. Treasury bonds are considered the world's safe-haven investment.
The Treasury Department issued an immediate response Wednesday.
"Moody's assessment is a timely reminder of the need for Congress to move quickly to avoid defaulting on the country's obligations and agree upon a substantial deficit reduction package," Treasury official Jeffrey A. Goldstein said in a statement.
In the still unlikely event the United States would default on any of its interest payments to bondholders, Moody's said it expected the default to be short-lived and the loss to bondholders "minimal or non-existent."
But, the agency added, a default "would fundamentally alter Moody's assessment of the timeliness of future payments." Translation: The United States would be downgraded to AA status.
Beyond the debt ceiling: Even if lawmakers raise the debt ceiling in time, Moody's also made clear that it is expecting progress on the long-term debt.
The agency said it would likely change its outlook on the AAA rating to "negative" from "stable" absent a "substantial and credible" debt-reduction deal.
Moody's had alerted investors in early June that it was considering putting the U.S. rating under review unless it saw forward movement in the debt talks by mid-July. It cited as a concern the "heightened polarization" in the debate.
Market reaction: Just how the bond market -- i.e., the investors around the world who lend to the federal government -- will respond to Moody's action is not clear yet.
Bond traders may take note but not blink since the agency already signaled its intention -- "so no surprise factor," said Steve Van Order, a fixed income strategist at Calvert Investments.
And Moody's isn't the ultimate arbiter.
"The bond market will follow its own judgment of how Washington is approaching deficit reduction, not the decisions of the rating agencies," said Jim Vogel, head of interest rate strategies at of FTN Financial.
But, Vogel noted, "Moody's action will focus the market's attention on the debt ceiling more than it has been in recent days. Rating agency actions also may provide a rationale for policy makers to alter their voting stance as deadlines loom."
Moody's isn't the first ratings agency to announce a negative action.
In April, Standard & Poor's revised its outlook on the country's AAA rating to negative from stable.
S&P's reason: Relative to its peers, the United States has "very large budget deficits and rising government indebtedness and the path to addressing these is not clear to us."
Fitch Ratings, meanwhile, said in early June that if lawmakers fail to raise the debt ceiling by Aug. 2, it would put the country on "ratings watch negative," meaning there is a "heightened probability" of a rating change.
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