Wall Street is getting increasingly nervous about the prospects for recession, both on a global and domestic level.

Slowing global growth has been one of the predominant investing themes in 2015, causing enough turmoil to send both the and the MSCI World Index down about 4 percent.

The $73.5 trillion global economy is expected to grow 3.1 percent in 2015 and 3.6 percent in 2016, according to the latest International Monetary Fund projections. Those numbers, though, are heading lower and could be revised even more before all is said and done.

Citigroup economist Willem Buiter looks at the world landscape and sees an economy performing substantially below potential output, which he uses as the general benchmark for the idea of a global recession. With that in mind, he said the chances of a global recession in 2016 are growing.

"We think that the evidence suggests that the global output gap is negative and that the global economy is currently growing at a rate below global potential growth. The (negative) output gap is therefore widening," Buiter said in a note to clients. He added, "from an output gap that was probably quite close to zero fairly recently, continued sub-par global growth is likely to put the global economy back into recession, if indeed the world ever fully emerged of the recession caused by the global financial crisis."

Recessions aren't necessarily a bad things for investors.

In the 12 recessions after World War II, the S&P 500 has gone up six times afterwards and down the other six times. The average has been a decline of 3.1 percent, followed by a 12.9 percent increase six months out and 15.3 percent gain a year after, according to figures from Sam Stovall, U.S. equity strategist at S&P Capital IQ.