Greece's banks will need an estimated 10 to 14 billion euros of fresh capital to keep them afloat and more time before they reopen even if a deal is reached with European creditors on Sunday, a senior Greek banker told Reuters on Friday.
Greece submitted new reform proposals late Thursday that creditors could evaluate as early as Friday. The parliament in Athens is also scheduled to vote on the proposals later in the day ahead of Sunday meetings of euro zone leaders.
Chinese stocks extended gains on Friday, jumping for a second day following government intervention amid hopes of a Greece deal. European stocks also advanced, with the DAX closing nearly 3 percent higher.
In domestic news, Fed Chair Janet Yellen said in prepared remarks the U.S. is still on pace for a rate hike this year and that fundamentals are solid and sees pickup in growth in the coming years.
"It confirms our belief that it will be a small hike and later this year," said Mariann Montagne, senior investment analyst at Gradient Investments. She expects a hike in November or December.
Yields extended morning gains with the U.S. 10-year note yield at 2.40 percent and the 2-year yield at 0.65 percent. German 10-year bund yields leaped to 0.89 percent.
Earlier, Boston Fed President Eric Rosengren said in a Reuters report that the central bank might hike rates later this year as long as inflation firms and Greece and other international wildcards do not get in the way. He added that negotiations over Greek debt and a slowing Chinese economy were among the possible disruptions that could delay the beginning of tighter U.S. monetary policy, though they hadn't altered expectations yet.
The U.S. dollar fell about half a percent, with the euro above $1.11.
"The likelihood of a Grexit has dramatically diminished," said Doug Cote, chief market strategist at Voya Investment Management. "Despite the volatility, despite the noise from Greece we're having good fundamental data coming out in (U.S.) housing. ... The fundamentals continue to drive this market forward."
In economic reports, U.S. wholesale trade inventories for May jumped 0.8 percent, soundly topping estimates for the fastest pace of growth in six months. April's figure was unchanged, showing a 0.4 percent gain.
There are no major earnings due on Friday.
Stocks rallied sharply in the open Thursday but gave back the majority of their gains to close mildly higher as lack of resolution on Greece kept investors on edge.
"We were very oversold so it's very important that we rally next week," said Lance Roberts, general partner of STA Wealth Management. He's watching to see if the S&P 500 can hold 2,078.
He expects a rate hike in September unless the situation in China worsens.
"The one thing that trips up markets is the story no one is talking about," he said.