First, the communications giant has a new chief financial officer, Deborah Hopkins, who could have the unenviable task of lowering estimates for the company's fourth quarter and beyond. Second, the company needs to show evidence that its 10 Gbls optical system is winning customers. And third, Lucent executives will face questions regarding the rumored spinoff of Lucent's Microelectronics business unit. Complicating these issues is Lucent's stock price, which is treading water just slightly above its 52-week low

Analysts surveyed by First Call estimate that Lucent will show year-over-year earnings per share growth of about 17%, to 29 cents per share, and revenue growth of 21%, to $9 billion. That does not include the spinoff of Avaya, the enterprise networks group.

"The quarter will be OK, and the balance sheet should improve, but what will be interesting is what they say about the outlook going forward," said Nikos Theodosopoulos, managing director of UBS Warburg.

Investors' primary concern should be the expectations of growth and the impact it has had on Lucent's balance sheet, said Steven Levy, analyst at Lehman Brothers.

"The quarters are backend loaded, the balance sheet is stretched and account receivables and vendor financing are up year over year;' Levy said. "I do expect that they will somehow revise guidance downward for the fourth fiscal quarter and fiscal 2001."

In the second quarter, Lucent announced more than $1 billion in new contracts for optical networking products. Overall growth for the product sector is expected to continue, but how fast the newly shipping OC-192 product gains sales traction remains.a question. Lucent landed $300 million in contracts during the second quarter.

"The OC-192 product should be a primary catalyst for revenue growth in the second half of 2000," said Greg Geiling, J.P. Morgan Securities analyst, in a report. Lucent tripled optical manufacturing capacity in the second quarter and expects to double it again in the third quarter, he said.

Most analysts view a potential spinoff of Lucent's Microelectronics unit as positive, although Lucent officials have not confirmed whether the much-speculated spinoff is even being considered.

"The business would have a higher valuation as a stand-alone company as opposed to being part of Lucent," Theodosopoulos said. "It would increase employee retention within Microelectronics where there's been an increasing level of turnover in the past year."

Although the deal also would unlock significant value for shareholders, it also would excise a piece of Lucent's business that is growing at a 20% to 25% clip."Microelectronics could grow faster on its own, but the problem with the spinoff is that it could make Lucent's [overall] balance sheet look that much worse." Levy said.

Lucent is scheduled to report actual earnings on July 20.

Lucent shocked investors late last year by reducing its revenue by hundreds of millions of dollars.

The S.E.C. investigation is the latest blow to Lucent, whose shares, down 70 percent in the last year, fell another 9 percent yesterday, shedding $1.53, to $15.36. The maker of communications equipment, based in Murray Hill, N.J., announced plans last month to lay off 10,000 employees and take a restructuring charge of at least $1.2 billion.

''It's a miserable situation,'' said Tom Lauria, an analyst at ING Barings who covers Lucent and competitors like Nortel Networks and Cisco Systems, which have taken business away from Lucent in recent months. ''It makes me wonder about how long Lucent can survive in its current form.''

Like some other analysts, Mr. Lauria has speculated that Lucent might eventually be divided into several companies under a plan similar to that of AT&T, which is splitting itself into four companies. Lucent became an independent company after AT&T spun it off in 1996.

The investigation into Lucent's accounting practices comes after the company unexpectedly cut its revenue by $679 million for the quarter that ended last September. The investigation is expected to cover the year through Sept. 30, 2000. Lucent began contact with the S.E.C. in late November when an internal review disclosed signs of problems, a spokeswoman for the company said.

As part of its own internal investigation, Lucent dismissed one high-ranking sales executive on charges of deceiving the company's finance team about credits he offered to Winstar Communications, a local communications carrier. The actions by the executive, who supervised Lucent's sales to new communications companies from an office in Dallas, led Lucent to revise its quarterly revenue downward by $125 million.

The executive has not yet received a subpoena from the S.E.C. to discuss the matter, a person close to the investigation said. The executive could not be reached for comment yesterday.

The revenue reduction also resulted in Lucent's subtracting more than $400 million in sales of equipment to companies that returned the items. Tighter financing for communications companies and a slowdown in their spending last year came at a time when Lucent was trying to meet aggressive growth targets promoted by Richard A. McGinn, the company's former chief executive.

Mr. McGinn was dismissed by Lucent's board in October and replaced by Henry B. Schacht, who was Lucent's first chief executive after its spinoff from AT&T in 1996.

It is unclear how the investigation will affect senior finance officials at Lucent, which has been unsuccessful so far in its search for a new chief executive to replace Mr. Schacht.

The investigation will cover a period in which the company had two chief financial officers. Lucent hired Deborah C. Hopkins as finance chief from the Boeing Company and paid her a $4 million cash signing bonus, in addition to stock options, in April. She replaced Donald K. Peterson, who became chief executive of Avaya, a maker of communications systems for businesses that Lucent spun off as a separate company last year.

The investigation by the S.E.C. follows complaints by Lucent shareholders, former employees and business partners.

In one lawsuit filed late last year, Nina Aversano, former president for sales in North America for Lucent, contended that Mr. McGinn forced her to retire from the company after she said in a detailed presentation in October that the company's sales targets were unrealistic.

''The investigation supports my client's claim that Lucent was in effect mortgaging its future to meet the short-term goals of its leadership,'' said Edwin G. Schallert, a partner at Debevoise & Plimpton, a law firm in New York representing Ms. Aversano.

Officials at the S.E.C. declined to comment on the investigation, which was reported yesterday in The Wall Street Journal. Lucent has twice sent representatives to Washington, in November and December, to provide detailed information on the company's accounting practices, people close to the investigation said.

''We fully expected that after initiating contact with the S.E.C., they would look into this matter thoroughly and completely,'' Lucent said in a statement yesterday. ''That is what they are doing. The S.E.C. has made no charges of any kind.''

Although the S.E.C. has not reported any wrongdoing at Lucent, its elevation of the investigation to a formal inquiry from an informal one gave optimism to lawyers representing shareholders in class-action lawsuits against the company.

Nearly a dozen lawsuits have been filed in recent months, after the decline in the company's market value from more than $270 billion to little more than $50 billion in the last year. Lucent is one of the nation's most widely held stocks.

''This is another arrow in my quiver,'' said Michael Lange, a partner at Berman DeValerio & Pease, a law firm in Boston that filed a lawsuit against Lucent in December. ''When the S.E.C. upticks to formal from informal it raises eyebrows about the possibility of reckless behavior.''

Analysts' main concern yesterday appeared to be whether the investigation would lead Lucent to make additional revenue reductions for quarters other than the one that ended on Sept. 30. Until yesterday, the company had appeared to put the worst behind it after reporting a loss of $395 million, or 12 cents a share, for the most recent quarter. There was a rally in Lucent shares in January that increased their value 40 percent.

''The investigation may probe additional quarters leading to added restatements, and also change revenue-recognition policies going forward,'' Michael E. Ching, an analyst at Merrill Lynch, wrote in a report. ''If this is the case, we will need to modify our earnings model.''