NEW YORK (CNN/Money) - While several big firms have come under scrutiny recently for questionable accounting practices, investigations of shady business practices are nothing new.

Before WorldCom, Enron and Adelphia made headlines, the savings & loan crisis was at the top of the accounting scandal list, and long-ago schemes by Charles Ponzi and Ivar Kreuger, among others, wiped out millions of investors' dollars.

Bernie Ebbers

Still, WorldCom and Enron can claim pride of place as two of the biggest accounting scandals to rock the financial world.

WorldCom (WCOM: Research, Estimates), one of the big success stories of the 1990s, said late Tuesday it will have to restate its financial results to account for billions of dollars in improper bookkeeping after an internal audit showed transfers of about $3.06 billion for 2001 and $797 million for the first quarter of 2002 were not made in accordance with generally accepted accounting principles.

Kenneth Lay

WorldCom, whose shares once traded above $64, tumbled to 21 cents in pre-market trading Wednesday.

The SEC and federal prosecutors began probing Adelphia Communications in May for allegedly inflating subscriber numbers and also is investigating possible misdeeds involving an estimated $3.1 billion in loans to the company's founding Rigas family.

Houston-based Enron, once one of the biggest companies in the nation, filed the largest bankruptcy in U.S. history last Dec. 2. Enron allegedly used thousands of off-the-books partnerships to hide nearly $1 billion in debt and to inflate profits.

Dennis Kozlowski

Dennis Kozlowski, Tyco's former chairman and CEO, was indicted in June on charges of evading more than $1 million in sales tax on rare paintings by Renoir, Monet and other artists. The widening criminal probe includes claims the company bought homes and artwork for executives without reporting it. Tyco (TYC: up $0.49 to $12.46, Research, Estimates) shares are down about 75 percent year-to-date as investors fret that the company, hit by a series of scandals, overstated profits.

Three former Rite Aid executives and a current manager were hit with federal criminal charges last week involving alleged securities and accounting fraud that forced the drugstore chain to restate more than $1 billion in earnings. A U.S. attorney charged the executives colluded in overstating Rite Aid's income in every quarter from May 1997 to May 1999, forcing the company to restate results by $1.6 billion, the largest restatement ever recorded, according to the SEC.

Merrill Lynch, one of Wall Street's biggest brokerage houses, came under fire from New York State Attorney General Eliot Spitzer in April, when Spitzer accused the firm's analysts of recommending questionable stocks to the public to benefit Merrill's investment banking arm. Although Merrill Lynch (MER: up $1.01 to $39.10, Research, Estimates) admitted no wrongdoing, the company has agreed to pay $100 million in fines as part of a settlement.

In the summer of 2000, Waste Management (WMI: down $0.46 to $26.66, Research, Estimates) and Arthur Andersen agreed to pay $229 million to settle a shareholder lawsuit over years of questionable accounting practices. Waste Management took a $3.5 billion charge in 1998 related to accounting irregularities.

About a year later, Andersen agreed to pay a $7 million civil fine after the SEC accused it of "knowingly or recklessly" issuing false and misleading audit reports for Waste Management for the years 1993 though 1996 that inflated the company's earnings by more than $1 billion. In November, Waste Management paid $457 million in fines to settle charges of violating securities laws in its 1998 merger with USA Waste Services and its 1999 financial statements.

In April 2000, Cendant Corp., the travel and transportation conglomerate that owns Ramada hotels and the Avis car rental chain agreed to pay $2.8 billion for engaging in irregular accounting practices to inflate earnings. The suit alleged that CUC International, which merged to form Cendant (CD: up $0.35 to $15.50, Research, Estimates) in 1997, issued false and misleading statements and charged that company officers sold Cendant stock before the announcement of the accounting problems.

Appliance maker Sunbeam Corp. (SOC: Research, Estimates) was forced to restate financial results for 1996 and 1997 in May 2001, and the SEC sued former CEO Al Dunlap [Chainsaw Al] and other executives after he was accused of using phony accounting to boost profits. The company later filed for bankruptcy.

One of the earliest of the 20th Century's financial rogues was Italian immigrant Charles Ponzi, who served time in Canada for forgery before setting up a business in Boston and London when he discovered he could buy international postal coupons abroad, then resell them in the U.S. for a higher price.

In what's now known as a "Ponzi scheme," or pyramid scheme, Ponzi pooled money from his initial investors, who made a profit off the venture, thus attracting more investors. But Ponzi soon stopped buying the coupons and paid off the early investors with the money poured in by the latecomers.

Another major scandal early in the century involved an international scheme operated by the "Match King," Ivar Kreuger, who held a virtual monopoly on household match production in Europe. After World War I, Kreuger, a Swede, backed by U.S. capital, lent money to war-torn countries in exchange for monopoly rights to the match business. But his business began to flounder amid the world financial tumult of the late 1920s, and in 1932 he committed suicide. After his death, it was discovered that his accounts were falsified -- and U.S. investors had been fleeced out of millions through the fraud.

Charles Keating, Jr.

The central figure in the Savings & Loan debacle of the 1980s was Charles Keating Jr., the former CEO of Lincoln Savings & Loan in Irvine, Calif., which was seized by regulators in 1989. Keating was convicted of securities fraud for allegedly looting the S&L and bilking investors of $200 million. He served more than four years in prison before getting the charges thrown out. In April 1999, Keating pled guilty to four felony counts in a deal to keep him out of prison.