NEW YORK (AP) — Investors agonizing over a faltering economy sent the stock market plunging all over again Wednesday after two disheartening reports convinced Wall Street that a recession, if not already here, is inevitable. The Dow Jones industrials dropped as much as 572 points, more than half their huge 936-point advance from Monday, and all the major indexes fell at least 5 percent.

The government’s report that retail sales plunged in September by 1.2 percent — almost double the 0.7 percent drop analysts expected — made it clear that consumers are reluctant to spend amid a shaky economy and a punishing stock market.

The Commerce Department report was sobering because consumer spending accounts for more than two-thirds of U.S. economic activity. The reading came as Wall Street was refocusing its attention on the faltering economy following stepped up government efforts to revive the stagnant credit markets.

The release of the Beige Book, the assessment of business conditions from the Federal Reserve, added to investors’ angst. The report found that the economy continued to slow in the early fall as financial and credit problems took a turn for the worse. The central bank’s report supported the market’s belief that difficulties in obtaining loans have choked growth in wide swaths of the economy.

‘‘Even though the banking sector may be returning to normal, the economy still isn’t. The economy continues to face a host of other problems,’’ said Doug Roberts, chief investment strategist at ChannelCapitalResearch.com. ‘‘We’re in for a tough ride.’’

Fed Chairman Ben Bernanke offered a similar opinion, warning in a speech Wednesday that patching up the credit markets won’t provide an instantaneous jolt to the economy.

‘‘Stabilization of the financial markets is a critical first step, but even if they stabilize as we hope they will, broader economic recovery will not happen right away,’’ he told the Economic Club of New York.

Analysts have warned that the market will see continued volatility as it tries to recover from the devastating losses of the last month, including the nearly 2,400-point plunge in the Dow over eight sessions. Such turbulence is typical after a huge decline, but the market’s anxiety about the economy is also expected to cause gyrations in the weeks and months ahead.

Investors apparently have come to believe that Monday’s big rebound, a response to the government’s plan to invest $250 billion in banks to get the lending business restarted, was overdone given the problems elsewhere in the economy.

‘‘It really doesn’t come as a shock after Monday’s gains were I think a little bit excessive,’’ said Charles Norton, principal and portfolio manager at GNICapital, referring to the market’s pullback.

He contends that the government has taken so many steps that investors must now wait for some of the actions to help steady the economy.

‘‘It seems like all the tools in the tool chest have mostly been used now and now it’s back to reality,’’ he said. ‘‘We’re still faced with the fact that the economy is slowing and earnings aren’t very good.’’

Doubts about the economy were already surfacing in Tuesday’s session, when investors halted an early rally and began collecting profits from stocks’ big Monday advance. Wednesday’s data confirmed the market’s fears that the economy is likely to remain weak for some time, and that corporate profits are likely to suffer.

Mark Coffelt, portfolio manager at Empiric Funds, said moves by European and U.S. government officials to begin investing directly in banks are easing worries about credit. But the steep pullback in stocks that began last month after the credit markets lurched to a near standstill has now created worries that consumers will spend less after seeing the value of their retirement accounts and other investments drop.

‘‘Markets abhor uncertainty and so we got a lot of that resolved this weekend and we got the reward Monday but now people are saying ’OK, now what is the economy going to do?’’’

‘‘We’re definitely going to get a slowdown from the terror of going through that,’’ Coffelt said.

In late afternoon trading, the Dow fell 544.15, or 5.84 percent, to 8,766.84 after falling more than 572.67 shortly after the release of the Beige Book.

Broader stock indicators also skidded. The Standard & Poor’s 500 index fell 69.99, or 7.01 percent, to 928.02, and the Nasdaq composite index fell 110.25, or 6.20 percent, to 1,668.76.

With Wednesday’s drop likely to hold, the Dow will, after a one-day break, resume a string of triple-digit losses or gains. On Tuesday, after swinging erratically throughout the session, the blue-chip index closed the day down a moderate 76 points.

The stock market was trying to recover from last week’s terrible run, which erased about $2.4 trillion in shareholder wealth and brought the Dow to its lowest level since April 2003. The tumble occurred amid a seize-up in lending stemming from a lack of trust among institutions in response to the bankruptcy of investment bank Lehman Brothers Holdings Inc. and the failure of Washington Mutual Inc., which had been the nation’s largest thrift.

The credit markets have been showing tentative signs of recovery, though they remain strained, and demand for safe assets remains high. The three-month Treasury bill on Wednesday was yielding 0.33 percent, up from 0.21 percent on Tuesday. Overall yields remain low, showing that demand is so high that investors are willing to earn meager returns as long as their principal is preserved.

The yield on the benchmark 10-year Treasury note, which moves opposite its price, fell to 4.01 percent from 4.03 percent late Tuesday.

Meanwhile, the Labor Department said the producer price index, which measures inflation pressures before they reach the consumer, fell 0.4 percent in September, driven by lower energy costs. That decline matched analysts’ expectations.

In corporate news, Intel Corp., topped analysts’ estimates and posted a third-quarter profit increase of 12 percent. Shares of the world’s largest maker of PC microprocessors fell 44 cents, or 2.8 percent, to $15.49.

JPMorgan’s results topped forecasts but the problems seen in all types of loans, not just home equity debt but also prime mortgages and credit cards, is worrisome for the banking industry. The stock fell 63 cents to $40.08.

Wells Fargo rose $1.17, or 3.5 percent, to $34.69 after its report.

Declining issues outnumbered advancers by about 7 to 1 on the New York Stock Exchange, where volume came to 1.1 billion shares.

The Russell 2000 index of smaller companies fell 35.69, or 6.43 percent, to 518.96.

In Asian trading, Hong Kong’s Hang Seng Index lost nearly 5 percent after rising more than 13 percent the previous two days. Markets in Australia, South Korea, China, India and Singapore also sank. Japan’s Nikkei 225 index, however, ended up 1.1 percent after soaring 14 percent in the previous session.

In Europe, Britain’s FTSE 100 fell 7.08 percent, Germany’s DAX index fell 6.49 percent, and France’s CAC-40 fell 6.82 percent.