Target reported third-quarter earnings and comparable sales below estimates on Tuesday at a time when a strong economy has boosted consumer spending at rival retailers, sending its shares sliding 12 percent in pre-market trading.

Target’s performance spooked investors during the critical holiday season as competitors including Walmart and Macy’s boosted sales during the same period.

The Minneapolis-based retailer said it gained market share in all key product categories in the quarter and remained confident it could reach its earlier full-year earnings outlook and hold its own during the key holiday season.

Target will offer free two-day shipping on hundreds of thousands of items through Dec. 22 with no minimum order or membership required.

Sales at stores open at least a year rose 5.1 percent, short of analysts’ estimates of a 5.21 percent increase, according to IBES data from Refinitiv. The company expects same-store sales to rise about 5 percent in the final quarter, signaling a slowdown ahead.

Profit missed expectations as price cuts, higher wages and investments in its online business ate into margins. Excluding items, Target earned $1.09 per share in the quarter, below the average estimate of $1.12 per share.

Gross margins were 28.7 percent, falling short of the estimate of 29.55 percent.

Online sales soared 49 percent during the quarter, outpacing a 41 percent rise in the second quarter and a 28 percent gain in the first quarter. But overall sales totaled $17.59 billion, below the average estimate of $17.8 billion.

Its third-quarter performance comes after it reported its best comparable-sales growth in 13 years during the second quarter.

Target shares dropped 12 percent, to $68.24, in pre-market trading.