NEW YORK (TheStreet) -- The markets will just have to wait a little longer.

The Federal Reserve ended weeks of intense speculation Thursday by deciding to hold interest rates at near-zero levels for now. But the central bank is unlikely to wait much longer, putting investors back into an anxious wait-and-see mode.

In her press conference after the decision was announced, Fed Chair Janet Yellen reiterated that a rate hike is still likely by the end of the year.

"October remains a possibility," Yellen said, referring to the Fed's next scheduled policy meeting.

Stocks immediately spiked after the decision but then zigzagged as investors tried to figure out what's next.

"It's basically just a knee-jerk reaction," Mike Meyer, vice president at EverBank World Markets, told TheStreet on market reaction. "We still have the uncertainty as to whether or not the Fed is going to raise rates this year."

In its statement, the Fed said the economy was continuing to expand "at a moderate pace." But the statement also noted "recent global economic and financial developments may restrain economic activity somewhat."

In her press conference, Yellen noted that the Fed is now considering what's going on in financial markets nearly as much as economic data.

Some analysts were quick to praise the Fed, saying that wage growth and labor participation were still too stagnant. Others were already anticipating a Fed rate hike, noting that the divergence from what other central banks are doing "will lead to further investment opportunities."

Uncertainty about the first U.S. interest rate increase in nearly a decade has been buffeting markets for months.

"The investing public, as well as the professionals, are in massive confusion--even chaos," contributor Ken Goldberg wrote this week in The Street.

The debate has centered on whether the U.S. economy has recovered enough from the 2008 financial crisis to allow rates to go back to "normal" levels. But a host of other issues has made the Fed's decision excruciatingly difficult.

Chief among them was the recent selloff in global stock markets, which prompted many pros to call for the Fed to hold off.

The Fed clearly seems hesitant to act while markets are in turmoil and investors are worried about China's slowing economy.

There also are fears that the global economy has gotten so used to low U.S. interest rates that any increase could damage everything from U.S. home sales to emerging markets

"As the Fed raises rates, both the domestic economy and global markets will push back," economist Peter Morici wrote recentlyin The Street.

Still, there are just as many pundits who think the Fed needs to raise rates--if not now, then soon.

"The economy and financial system have come a long way and the need for zero interest rates has passed," Mark Zandi, chief economist of Moody's Analytics, wrote in The Street this week.

"The longer they wait to normalize monetary policy," Zandi warned, "the greater the risk they will wait too long and are ultimately forced to raise rates quickly."

There also is confidence in some quarters that markets can  survive a rate increase and could even move higher.

All this has has left Fed Chair Janet Yellen and the other policymakers in a bind.

"This isn't an easy decision," Zandi said in his commentary this week.

For now, the markets will just have to wait until October--or maybe even December--for the Fed to act.

In the meantime, here are some articles to help get you through the coming weeks.

This article was written by a staff member of TheStreet.