Rival electronics discounters Best Buy ( BBY) and Circuit City ( CC) each posted quarterly results that beat analysts' estimates Tuesday morning. Richmond, Va.-based Circuit City said it lost $21.3 million, or 10 cents a share, in its third quarter, compared with its year-ago profit of $9.2 million, or 4 cents a share. Analysts, who lowered their estimates when Circuit City issued a profit warning in early November, had been predicting a loss of 13 cents a share, on average, for the latest third quarter. Sales rose 7% to $2.42 billion from $2.26 billion. Same-store sales rose 6% in the quarter, but the company said its gross profit margin fell because of higher sales of entertainment software, "entry-level products" and personal computers, and weaker sales of wireless and digital satellite systems. Minneapolis-based Best Buy earned $85 million, or 26 cents a share, in its third quarter, compared with $80 million, or 25 cents a share, last year. Analysts had been expecting earnings of 25 cents a share. Quarterly sales jumped 16% to $5.5 billion.