* S&P 500 hits resistance at 2013 year-end mark
* Target and Lowe's rally after results
* J.C. Penney shares jump after the bell
* January new home sales surge past forecasts
* Dow up 0.1 pct; S&P 500 flat; Nasdaq up 0.1 pct
NEW YORK, Feb 26 (Reuters) - U.S. stocks finished flat on Wednesday with investors hesitant to make a big move on the day before comments from Federal Reserve Chair Janet Yellen, though retailers' shares rallied on results for a second day.
Target Corp and Lowe's Cos Inc shares jumped following upbeat earnings and gave the biggest boosts to the S&P 500. An S&P 500 retail index gained more than 1 percent for a second day.
After the bell, shares of J.C. Penney Co Inc climbed 12.8 percent to $6.72 as the U.S. department store chain forecast more improvement in its comparable sales and gross profit margin this fiscal year.
The S&P 500 once again briefly broke above its 2013 year-end closing level of 1,848.36, which has served as resistance, but failed to hold above it, analysts said. The index remained down 0.2 percent for the year.
"From a technical perspective, we're battling with the year-to-date break-even mark on the S&P," said Todd Salamone, vice president of research at Schaeffer's Investment Research in Cincinnati, Ohio. "It just seems ... there's no firm commitment to drive the S&P back above this particular level."
But he said the market also seems to be biding time until Thursday, when Yellen addresses the Senate Banking Committee in semiannual testimony about monetary policy. This appearance, originally set for Feb. 13, had to be postponed when Washington was walloped with the heaviest snowfall of the season.
Her comments will be scrutinized for insight into how much an unexpectedly cold winter has affected economic activity, and for confirmation that the Fed will maintain its stimulus-trimming schedule.
The Dow Jones industrial average rose 18.75 points or 0.12 percent, to end at 16,198.41. The S&P 500 inched up a mere 0.04 of a point to finish at 1,845.16. The Nasdaq Composite added 4.477 points or 0.10 percent, to close at 4,292.064.
The S&P 500 reached a record intraday high of 1,858.71 on Monday, but was unable to hit a record close.
The small-cap Russell 2000 index ., however, climbed to a record closing high of 1,181.72 on Wednesday.
Adding to investor anxiety were developments in Ukraine. Russian President Vladimir Putin put 150,000 combat troops on high alert for war games near Ukraine.
In the retail sector, Target's stock jumped 7 percent to close at $60.49 after the company reported results. The third-largest U.S. retailer said sales and earnings had been affected by a massive data breach and that costs relating to the event could hurt future profits.
Lowe's stock rose 5.4 percent to end at $50.72 after the No. 2 U.S. home improvement retailer reported earnings and sales growth and unveiled an additional stock-buyback program of $5 billion.
The S&P 500 retail index gained 1.4 percent. Wednesday's strong retail performance came a day after upbeat results from Home Depot and Macy's.
On the economic front, new home sales surged to a 5-1/2-year high in January, far exceeding expectations. While much recent data has been below forecasts, analysts have attributed that to bad weather rather than worsening fundamentals. The housing data could support that interpretation.
The day's decliners included First Solar Inc, whose shares fell a day after the U.S. solar panel maker reported that its fourth-quarter net income fell 58 percent. First Solar's stock slid 9.1 percent to end Wednesday's session at $52.74.
Among other after-the-bell movers, shares of Autodesk rose 3.7 percent to $56.76 following the release of the computer-aided design (CAD) software maker's results.
About 6.9 billion shares changed hands on U.S. exchanges, below the 7 billion average so far this month, according to data from BATS Global Markets.
Advancers beat decliners by a ratio of slightly more than 3 to 2 on both the New York Stock Exchange and the Nasdaq.