WASHINGTON (MarketWatch) — Standard & Poor’s has reportedly backed off a plan to strip the U.S government of its prized triple-A debt rating Friday after White House officials challenged the analysis and said the credit rater was “trillions” off in its analysis.

According to multiple reports, McGraw-Hill MHP, unit S&P told the government Friday afternoon of an imminent downgrade. But officials told the agency it was “trillions of dollars” off in its analysis, in part because of the complicated “baselines” that are used to compare long-term government spending and revenue projections, according to reports.

The rumored S&P downgrade was cited as a factor in Friday’s wild 416-point intraday swing in the Dow Jones Industrial Average.See Market Snapshot.

It’s not clear what the impact of an S&P downgrade of the U.S. would be, as fellow rating agencies Moody’s MCO, +1.44% and Fitch Ratings have affirmed their triple-A ratings. (Moody’s has warned that it may downgrade the U.S. in the future.)

Investors that are required by their mandates to only invest in triple-A debt may still be able to own Treasury bonds if only one firm lowers its U.S. debt rating. It’s also unclear whether Treasurys pledged as collateral in various derivatives trades as well as to secure Federal Reserve lending would be impacted.

In any case, investors have flocked to Treasurys this week, with government-bond prices seeing their biggest gains in two years, which indicates that investors have brushed off concerns that they won’t be paid back.

A Treasury-price run-up this week suggests an absence of default fear among investors. Treasury-bonds-notes.com

S&P staked out the most hawkish position of the agencies in the recently concluded debt-ceiling debate. On July 14, S&P said it would take $4 trillion in deficit reduction over a decade for the U.S. to secure its AAA rating. The deal signed into law this week achieves, at best, $2.1 trillion in deficit reduction, according to estimates from the nonpartisan Congressional Budget Office.

The rating agencies have been heavily criticized for their role in the credit crisis for not downgrading mortgage-backed securities, but there are few alternatives to their role.