More weak credit is hitting bottom lines — most recently at jewelry retailing icon Tiffany & Co.

Problems in its role as creditor led Tiffany & Co. to report fourth-quarter and full-year results that included a pre-tax impairment charge of $48 million, or 22 cents per diluted share, in its selling, general, and administrative expenses. The charge reflected the expectation that loans it made to Tahera Diamond Corp. will not be repaid.

Tiffany said that the charge represents the full amount of loans to the Canadian-owned diamond mining company, including accrued interest. “In January 2008, Tahera sought judicial protection from creditors,” Tiffany noted. Otherwise, Tiffany reported that net earnings per diluted share from continuing operations, excluding nonrecurring items, increased 19 percent, to $1.27 in the fourth quarter, and rose 22 percent for the year, to $2.33. Full-year revenue rose to $1.05 billion from $958.9 million in the prior year.

Meanwhile, on the receiving end of lending, troubled homebuilder Standard Pacific Corp. said that its bank group has agreed to extend a waiver of any default arising from the company’s noncompliance with financial covenants contained in its bank credit facilities. The default could result from the impact of deferred tax asset valuation allowance charges.

The waiver, originally due to expire on March 30, has been extended by 45 days, to May 14. Under the deal, the company in turn agreed to reduce its revolving credit facility commitment from $900 million to $700 million. As of March 21 the company had $90 million of borrowings and $49 million of letters of credit outstanding under the revolving credit facility.

Standard Pacific said it is continuing to negotiate with its lenders to amend its bank credit facilities.