Updated from 4:10 p.m. EDT

Stocks soared into the close Wednesday, reversing earlier losses, as the disappointment from the Federal Reserve dissipated and investors looked for buying opportunities.

At the end of the day, the Dow Jones Industrial Average had a gain of 260.92 points, or 3.1%, to 8743.31. Earlier, the Dow had been down by 130 points. The Nasdaq closed higher by 65.02 points, or 5.1%, to 1334.30, and the S&P 500 added 35.41 points, or 4%, at 919.62.

There was a similar swing in bond prices. Around 4 p.m. EDT, the price of 10-year Treasuries was down 8/32 at 102 2/32 with a yield of 4.120% after spending much of the day substantially higher. The 30-year bond was up 18/32 to 106 23/32, yielding 4.933%, but that was well below its best level of the session.

Given the vigor of both the buying in stocks and the selling in bonds, several traders suggested that the moves must be the result of asset-allocation programs in both markets. The possible influence of short-covering was also being raised by some observers.

In a story that developed throughout the day, hundreds of CEOs and chief financial officers of the biggest U.S. companies had to contend with the deadline to certify their results with the Securities and Exchange Commission.

All told, executives from the 947 largest companies ultimately will have to file sworn statements with the government attesting to the accuracy of their results. The majority of those had Wednesday afternoon as the deadline, but dozens of companies will have several more weeks to submit their statements.

On Tuesday, the Federal Open Market Committee , the Fed's policymaking arm, unanimously decided to leave interest rates unchanged at 1.75%, a 40-year low. The FOMC also cautioned that the economy could be in danger of weakening.

Following the announcement, the Dow closed down 206 points, or 2.4%, to 8482. The Nasdaq dropped 38 points, or 2.9%, to 1269, and the S&P fell 20 points, or 2.2%, to 884.

Among the companies facing Wednesday's SEC deadline is media titan AOL Time Warner ( AOL). After a lengthy internal debate, AOL plans to certify its accounting records in a filing with the SEC Wednesday, according to The Wall Street Journal. Company executives were reportedly split on whether to go ahead with the certification in light of various probes into some of their revenue recognition.

Now that more corporations -- even those that don't have to certify initially -- are scrutinizing their books for potential accounting irregularities, restatements are becoming commonplace. One of the latest companies to run into trouble is energy company Nicor ( GAS).

Nicor saw its shares shake off earlier selling pressure and rise 2% to $26.67 after announcing that it would restate its first-quarter results. The company also said it would be unable to authenticate its results to the SEC because of uncertainties surrounding its gas distribution business. In premarket trading, the stock had been off more than $5.

Switching gears, computer maker and Dow component IBM ( IBM) said in a filing after the close Tuesday that 15,600 workers were involved in job cuts that were announced in early June. According to the company's 10-Q report, 14,213 of the workers were in the company's Global Services business. Most left the company by the end of June. The rest will go by the end of next month.

Another 1,400 workers also were laid off, with the majority of that group leaving by the end of August. All those who were laid off were notified by June 30, according to the filing. The cuts total about 4.9% of IBM's worldwide workforce. IBM rose 4% to $74.92.

In another restructuring move, contract manufacturer Flextronics ( FLEX) said it plans to cut more than 5,200 jobs in an attempt to cope with an industrywide slowdown. Shares of Flextronics gained 12% to $8.49.

Network Appliance ( NTAP) was benefiting from a positive earnings report, trading up 28% to $9. After the close Tuesday, the company, which makes data storage devices, beat analysts' estimates by a penny and said it expects modest revenue growth and flat earnings in the current quarter.

Chip-equipment maker Applied Materials ( AMAT) posted a third-quarter profit that exceeded analysts' expectations, helped by a 5% rise in new orders. But the company offered weak guidance for the fourth quarter, warning that orders could drop 5% to 15% sequentially. The stock climbed 7% to $14.42.

Elsewhere, Federated Department Stores ( FD), which operates Macy's and Bloomingdale's, reported an increase in second-quarter earnings as reduced inventories helped offset weaker sales. The retailer posted a profit of 66 cents a share, compared with 50 cents a share in the year-ago quarter, topping analysts' forecasts by 4 cents. Shares of Federated were up 7% to $34.83.

One economic report was on the calendar, business inventories from the Commerce Department. According to the report, inventories rose 0.2% in June, matching a 0.2% increase in May and suggesting that companies are growing more optimistic about a rebound in the economy. The results were in line with economists' forecasts.

Overseas stocks were lower across the board. In Europe, London's FTSE 100 lost 2.4% at 4171, while Germany's Xetra DAX was down 2.5% at 3590. Japan's Nikkei 225 fell 0.5% to 9638, and Hong Kong's Hang Seng closed down 1.4% to 9961.