Over the three months to Feb. 1, the retailer earned $520 million, or 81 cents a share, down from $961 million, or $1.47 a share, in the year-ago quarter.
Revenue fell 5% to $21.5 billion, while U.S. comparable-store sales decreased 2.5%, consistent with prior guidance and a tick wider than analysts' expectations of a 2.4% decline. The company said it saw "meaningfully softer" sales following the announcement of the data breach on Dec. 19.
And the pain isn't over yet. Target said it is not able to estimate future expenses related to the breach, which saw around 40 million credit and debit cards and 70 million other records containing personal customer information compromised.
Potential expenses include claims for counterfeit fraud losses, card re-issuance expenses, civil litigation, governmental investigations, and legal and consulting fees.
"These costs may have a material adverse effect on Target's results of operations in first quarter and full-year 2014 and future periods," the company said in the statement.
For the current quarter, management said it expects adjusted earnings of between 60 cents and 75 cents a share and full-year earnings of $3.85 to $4.15 a share. Analysts surveyed by Thomson Reuters forecast 85 cents and $4.15 a share, respectively.
Wall Street doesn't seem fazed by higher expenses and lower earnings, though. By midmorning, Target shares had added 3.5% to $58.47.
Quarterly adjusted earnings of $1.30 a share beat consensus by 51 cents and total sales were $69.2 million higher than expected.