The FederalReserve held Wall Street rapt throughout a roller coaster of a week. The first half had analysts debating the chances of a September rate hike, followed by a relief rally over the central bank's decision to leave policy unchanged.

The two-day rally on Wednesday and Thursday pushed stocks to end the week in the green and the Nasdaq trading near records. Over the past five days the S&P 500 added 1.2%, the Dow Jones Industrial Average climbed 0.8%, and the Nasdaq rose 1.2%. 

The Fed opted to leave rates unchanged for another month following the conclusion of its two-day September meeting on Wednesday afternoon. Members said the case for an increase to the fed funds rate had strengthened but decided to wait for further evidence the economy was progressing toward its inflation and labor market objectives.

Kansas City Fed President Esther George, Cleveland Fed President Loretta Mester and Boston Fed President Eric Rosengren each called for a rate increase at the meeting. George was the sole dissenter at the previous meeting at the end of July.

Fed Chair Janet Yellen noted in a Wednesday press conference that economic growth had shown signs of recovery after a slowdown earlier in the year. Yellen reiterated a cautious approach to future rate increases and said that any moves would be gradual to achieve and maintain the central bank's objectives.

"We've found the economy has a bit more running room," Yellen said at the press conference. "Nevertheless, we don't want the economy to overheat and if things continue on the current course, I think that some gradual increases will be appropriate. Mainly, what we discussed today were issues affecting the timing of such increases."

The majority of investors are now pricing in the likelihood of a rate hike in December. Chances are now at 52%, according to CME Group fed funds futures, up from 48% before the announcement on Wednesday.

"The recent economic news has been OK, but not quite good enough," said Paul Eitelman, Multi-Asset Investment Strategist at Russell Investments. "Global concerns such as China's wobbling economy and the continued uncertainty from Brexit no doubt played a role in the Fed's thinking, as well. We still believe that U.S. interest rates are likely to go up in December."

Crude oil ended the week with a massive selloff as hopes of an production freeze agreement among the Organization of Petroleum Exporting Countries faded. An agreement is unlikely to come out next week when OPEC members meet while attending the International Energy Forum in Algeria, sources told Bloomberg

Oil ended with a weekly gain of 2%, though, after a mid-week read on U.S. inventories eased fears over domestic oversupply. The latest weekly reading on U.S. inventories showed a major decline of 6.2 million barrels, the Energy Information Administration reported on Wednesday. U.S. oversupply, weaker global demand and breakneck output from some of the world's largest oil producers have beaten down oil prices over the past two years.

In earnings news, Red Hat (RHT) - Get Report boosted earnings guidance thanks to a better-than-expected quarter, Bed, Bath & Beyond (BBBY) - Get Report reported an unexpected drop in comparable-store sales in its recent quarter as the retail environment remained competitive, and Rite Aid (RAD) - Get Report weathered a mixed quarter as sales of generics came under pressure.

Adobe (ADBE) - Get Report topped quarterly estimates on its top and bottom line, General Mills (GIS) - Get Report reported weaker sales due to a challenging macro environment, and FedEx (FDX) - Get Report lowered its fiscal 2017 guidance.

Wells Fargo (WFC) - Get Report and Mylan (MYL) - Get Report each got a congressional grilling this week. Wells Fargo CEO John Stumpf apologized to the Senate Banking Committee on Tuesday for the bank opening unauthorized accounts to drum up sales numbers. The bank now plans to eliminate sales targets beginning next year.

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Mylan CEO Heather Bresch testified before a congressional panel on Wednesday, justifying the price hikes of the drugmaker's life-saving EpiPens. The list price of EpiPens has grown to $608 for a two-pack, an increase of more than 500% since 2007.