U.S. stocks closed sharply higher Friday as oil prices rose and investors took a more positive view of Thursday's European Central Bank announcements on stimulus.
"The monetary policy tools we believe are effective are being expanded and the monetary policy tools we don't believe to work are being limited," said Art Hogan, chief market strategist at Wunderlich Securities.
Also supporting gains in stocks was a rise in oil following the International Energy Agency's report that said oil might have bottomed. Baker Hughes data showed U.S. rigs declined by six.
U.S. crude oil futures settled up 66 cents, or 1.74 percent, at $38.50 a barrel.
The major U.S. averages rallied more than 1 percent to swing into positive territory for the week, their fourth-straight week of gains since November.
Both the Dow and S&P 500 ended at their highest since intraday trade on Jan. 4, the first trading day of the year. As of Friday's close, the indexes were just about 1 percent lower year-to-date.
The S&P 500 gained 1.6 percent to top the psychologically key 2,000 level and close above its 200-day moving average for the first time since Dec. 30.
"2,000 — that's a level that has a certain magical quality about it," said Mark Luschini, chief investment strategist at Janney Montgomery Scott. "There's significant overhead resistance at 2,020 - 2,050."
The Dow Jones industrial average closed about 218 points higher, also above its 200-day moving average for the first time since Dec. 30.
"The reason not to buy is less. There's much more reason to participate now especially as the market grinds higher," said Jeremy Klein, chief market strategist at FBN Securities.
Concerns about China were also alleviated by the yuan's strongest midpoint fix against the dollar for the year so far. The PBOC set the peg at 6.4905 against the dollar on Friday, after the greenback's drop Thursday following the ECB stimulus announcements. The yuan's 0.34 percent move from the prior day's fix was the largest daily strengthening since November, according to StreetAccount.
"That obviously's been a bit helpful, the stabilization in the currency," said Peter Coleman, head trader at Convergex.
U.S. stocks closed mostly lower Thursday, under pressure from low oil prices and concerns about the effectiveness of monetary policy following the morning's announcements from the European Central Bank. The S&P 500 did manage to squeeze out a gain of less than one point.
On Thursday, the euro reversed an initial decline to hit its highest against the U.S. dollar in nearly a month after ECB President Mario Draghi surprised markets by saying he didn't anticipate a need to reduce rates further, although new facts can change the situation and the outlook.
"I think the reaction was a little bit rash and quick after all the information that came out yesterday," Coleman said.
"I think the fact that our markets rallied and stabilized a bit helped sentiment overseas. You got all the key risk-on factors up today," he said.
Gold futures for April delivery settled down $13.40 at $1,259.40 an ounce, while Treasury yields rose. The 2-year yield was 0.94 and the 10-year yield was around 1.98 percent.
The U.S. dollar index held a touch higher, with the euro near $1.115 and the yen at 113.77 yen against the greenback.
"I think with oil and rethinking (ECB President) Mario Draghi's powerful message that he sent to the markets, because he did do more than we were expecting ... I think that rethinking of the actions is going to lead the market higher along with higher oil prices," said Peter Cardillo, chief market economist at First Standard Financial.
However, skepticism on the sustainability of the recent rally remained.
BTIG Chief Technical Strategist Katie Stockton said in a note that indicators show that Friday's rally "will likely fail and give way to a loss of short-term momentum."
"Yesterday, the SPX registered an overbought "sell" signal intraday, although a relatively strong close prevented it from being confirmed. An outside-down day was narrowly avoided, as well, but the same cannot be said for the other major indices. The NASDAQ Composite Index and Russell 2000 Index both have overbought "sell" signals and outside-down days that support a broad-based pullback in the next two weeks," she said.
In U.S. economic news, February import prices declined 0.3 percent, while export prices fell 0.4 percent.
European stocks closed sharply higher Friday, with the German DAX up 3.51 percent.
Asian stocks reversed to close higher, with the Shanghai composite up about 0.2 percent and the Nikkei 225 half a percent higher. Both indexes still posted losses for the week.
Total social financing, an important indicator of China's credit expansion, fell sharply to 780.2 billion yuan in February from 3.42 trillion in January, Reuters said.
The Dow gained 1.2 percent for the week, with Chevron the top performer and Visa the worst.
The closed up 32.62 points, or 1.64 percent, at 2,022.19, with financials leading all 10 sectors higher.
The index rose 1.1 percent for the week, with materials and utilities leading all 10 sectors higher on the week.
The Nasdaq composite closed up 86.31 points, or 1.85 percent, at 4,748.47.
The Nasdaq gained 0.67 percent for the week. Apple fell 0.76 percent for the week.
The CBOE Volatility Index (VIX), widely considered the best gauge of fear in the market, traded below 17.
About five stocks advanced for every decliner on the New York Stock Exchange, with an exchange volume of 996 million and a composite volume of 4.0 billion in the close.
High-frequency trading accounted for 49 percent of March's daily trading volume of about 8.75 billion shares, according to TABB Group. During the peak levels of high-frequency trading in 2009, about 61 percent of 9.8 billion of average daily shares traded were executed by high-frequency traders.
—Reuters contributed to this report.