Heading into the central bank’s pronouncement on whether to raise interest rates for the first time since 2006, the only sure thing is how undecided investors are about the fate of the equities market. All depends on what the Federal Open Market Committee decides — will they or won’t they? — as well as how policy makers communicate their message.

Goldman Sachs Group Inc. said Wednesday that financial markets are vulnerable because nobody can agree on what the Fed will do. The Standard & Poor’s 500 Index has fallen on three of the past five days the Fed started a tightening cycle, with an average directional move of 1.4 percent. But previous rate moves may not be the best guide this time. The market has faced unprecedented volatility leading up to the meeting, including a 10 percent plunge over four days last month. 

The benchmark gauge declined less than 0.1 percent to 1,993.78 at 9:53 a.m. in New York.

Amid the tumultuous background, here are predictions of nine money managers and strategists on what to expect Thursday afternoon:

1) Crisis of Confidence

The Fed would be well-served to raise rates on Thursday to avoid a crisis of confidence among investors, according to Bill Schultz, who oversees $1.2 billion as chief investment officer at McQueen, Ball & Associates in Bethlehem, Pennsylvania. Market participants may see central bank inaction as a signal of concern over global economic growth, he said.

“If the Fed doesn’t do anything, it lends a bit more fear to the market that things are worse than expected,” he said. “In a funny way, the fact that they wouldn’t raise rates would send a little bit of concern into the market. It may not be the most well-received type of movement.”

2) No-Win Situation

To Kim Forrest, an analyst at Fort Pitt Capital Group Inc., which oversees about $1.7 billion in Pittsburgh, the stock market is doomed to fall no matter what the Fed does. With that in mind, the Fed should “just rip the band-aid off,” according to Forrest.

“It’s going to sell off either way because there’s so much tension built up into this,” she said. “If for some reason the Fed decides whatever the magic data is doesn’t exist right now, that could worry equity folks that there’s something the Fed sees that they don’t. If they actually do take the long-awaited 25 basis point, the market sells off as people say ‘wow it actually happened.”’

3) Win-Win Situation

Robert Pavlik, who helps oversee $9.1 billion as chief market strategist at Boston Private Wealth, is optimistic about U.S. stocks regardless of the Fed outcome. Both scenarios will provide an opportunity to scoop up U.S. shares that declined as much as 12 percent in the last month, but have recovered 6.8 percent since reaching a 10-month low on Aug. 25.

“If the Fed raises rates, initial selling will be followed by buying,” he said. “If we don’t get a Fed rate hike, I think it’s a signal that we have a few more months between now and December to rally risk-on stocks. I’m in the minority thinking that the market rallies either way.”

4) Short-Lived Moves

Whatever move stocks make in the Fed decision, the aftermath will quickly be reversed after investors have time to further digest the information, said John Stoltzfus, the New York-based chief market strategist at Oppenheimer & Co. It’s similar to what happened when the central bank started scaling back its bond-buying program, which concluded in October, he said.

“If they don’t go, the market will have a little rally and then start pondering why they didn’t go,” he said. “If they do, the market will likely first stumble and extrapolate negatively, but then they’ll realize it’s a good thing.”

5) More Volatility

To Michael Purves, chief global strategist at Weeden & Co in Greenwich, Connecticut, any move in U.S. stocks will blend into a volatile landscape that’s seen the S&P 500 alternate between gains and losses for the past nine weeks.

“You’ll probably see a 1 percent or so move up if the Fed doesn’t go, but in today’s market that’s like what used to be” a 0.2 percent move, he said. “We’ll trade up, but that doesn’t necessarily mean we’ll stay there.”

6) Importance of Pace

While many market participants are hung up on whether the Fed will raise rates, people like Bill Northey, the Helena, Montana-based chief investment officer at the Private Client Reserve at U.S. Bank Wealth Management, are more focused on the speed of the Fed’s movements.

“The pace is far more important than the original start date,” he said. “The Fed and the market have been a little divergent in terms of the longer term view of the path. We’re going to get some more color through the commentary.”

7) Other Assets

At Deutsche Bank AG, chief U.S. equity strategist David Bianco sees U.S. stock performance subject to other asset classes. After all, investors are also contending with a dollar close to its highest level in 10 years and rising yields on government debt.

“If the Fed hikes, we think the S&P can rally provided Treasury yields and the dollar don’t surge,” he wrote in a Sept. 11 note to clients. “Banks would likely outperform upon a hike.”

8) Overseas Concern

For Bruce Bittles, chief investment strategist at Milwaukee-based Robert W. Baird & Co., which oversees $110 billion, the stock market’s initial reaction could be overshadowed later by the response from overseas.

A “scenario that could upset things would be if foreign markets reacted harshly to a rate increase — like if China absolutely crashed,” he said. “That would be an outside factor beyond our control, which could have some influence.”

9) Clarity is King

All Greg Woodard wants is to know where he stands. The senior analyst and strategist at Fairport, New York-based Manning & Napier Inc., which oversees about $39 billion, favors decisive Fed guidance over any specific outcome.

“Our view is that the market likes certainty,” he said. “If you do get a decision this Thursday and the Fed communicates a slow and long process of normalization, that could add clarity.”