SAN FRANCISCO (AP) — Diamond Foods Inc. said Thursday that it will restate two additional quarters of financial data as the snack food company tries to clean up the fallout from its improper accounting of payments to walnut growers.

The company, which makes Emerald Nuts and Pop Secret popcorn, launched an internal investigation last year that ultimately found the company improperly accounted for payments to walnut growers in 2010 and 2011, which skewed its financial results.

Diamond suffered mightily from the problems. Its stock price sank as concerns built about the payments, it lost its bid to buy the Pringles brand from Procter & Gamble Co., and it eventually replaced its CEO and chief financial officer over the issue.

The company had previously said that it would restate its quarterly financial results for all of 2011 and the fiscal fourth quarter of 2010. In addition, it would restate its full fiscal year results for both 2010 and 2011.

Diamond said Thursday that it will now restate two more quarters, updating the financial statements from the second and third quarters of fiscal 2010 to adjust for walnut cost estimates during that time.

The company's interim Chief Financial Officer Mike Murphy said Diamond's finance team has been working diligently to complete the restatements and is nearing completion.

Diamond's shares have lost nearly 80 percent of their value since the fall of 2011 when news of the payment issues became known.

Its stock price increased nearly 2 percent in after-hours trading Thursday as investors welcomed a sign that some resolution may come soon. Shares closed regular trading at $18.57 and increased 33 cents to $18.90 after hours.