* Walmart drops after holiday-quarter profit misses estimates
* Amazon, tech, bright spots on Nasdaq
* Dow down 1.01 pct, S&P 500 down 0.58 pct, Nasdaq off 0.07 pct (Updates with market close)
By Chuck Mikolajczak
NEW YORK, Feb 20 (Reuters) - The Dow and S&P 500 fell on Tuesday to snap a six-session winning streak as a sharp decline in Walmart weighed heavily, but gains in Amazon and chip stocks helped the Nasdaq hold near the unchanged mark.
Walmart, the world's biggest brick-and-mortar retailer, reported a lower-than-expected profit and posted a sharp drop in online sales growth during the holiday period. Its shares slumped 10.2 percent, and suffered their biggest percentage fall since January 1988.
Markets have been choppy in recent weeks, falling more than 10 percent from their Jan. 26 high only to rebound last week with their best weekly gain in five years. Tuesday's declines once again pushed the S&P 500 below the 50-day moving average, a technical support level.
"The basic framework in terms of the economic landscape and earnings have not really changed, although clearly Walmart has driven some fear into the market," said Peter Kenny, senior market strategist at Global Markets Advisory Group, in New York.
"We are looking for a confirmation, a technical confirmation the markets are on solid footing."
The report pulled other grocery retailers lower, with Target , off 3 percent and Kroger down 4.2 percent. The S&P consumer staples index dropped 2.25 percent and is down nearly 5 percent for the year.
In contrast, shares of online retailer Amazon climbed 1.4 percent.
The Dow Jones Industrial Average fell 254.63 points, or 1.01 percent, to 24,964.75, the S&P 500 lost 15.96 points, or 0.58 percent, to 2,716.26 and the Nasdaq Composite dropped 5.16 points, or 0.07 percent, to 7,234.31.
The initial market selloff in January was sparked after economic data raised worries the economy may overheat, causing a quick spike in bond yields and concern the Federal Reserve may become more aggressive in raising U.S. interest rates.
While still near four-year highs, yields have leveled off somewhat of late, as benchmark 10-year U.S. Treasury notes last fell 4/32 in price to yield 2.8896 percent, from 2.877 percent late on Friday.
The S&P technology index gained 0.3 as the sole major S&P sector on the plus side, buoyed by a gain of nearly 2 percent in the semiconductor sector.
Qualcomm fell 1.3 percent after the chipmaker raised its offer to buy NXP Semiconductors NV to $127.50 per share from $110. NXP shares jumped 5.96 percent.
"What is going on with Qualcomm and their bid for NXP is certainly making all the semiconductors look more attractive," said JJ Kinahan, chief market strategist at TD Ameritrade in Chicago.
Home Depot edged down 0.14 percent after the largest U.S. home improvement chain's quarterly profit beat market estimates in an improving housing market.
Declining issues outnumbered advancing ones on the NYSE by a 1.98-to-1 ratio; on Nasdaq, a 2.05-to-1 ratio favored decliners.
The S&P 500 posted 14 new 52-week highs and one new low; the Nasdaq Composite recorded 86 new highs and 30 new lows.
Volume on U.S. exchanges was 6.79 billion shares, below the 8.48 billion average over the last 20 trading days. (Reporting by Chuck Mikolajczak; Editing by James Dalgleish)