Four big market questions

Geopolitics aside, here are my four biggest market questions heading into fall:

WWTFD (What will the Fed do)?

Perhaps a better question is WWTFS — what will the Federal Reserve say. With just three Fed meetings left this year there is essentially no chance Yellen & Co will move on interest rates. Most are pointing toward mid-2015 as the first rate increase. The only real "what if" regarding the Fed is the language it uses in future statements.

Traders on the floor of the New York Stock Exchange.
Lucas Jackson | Reuters
Traders on the floor of the New York Stock Exchange.

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Any turn toward a more hawkish tone could send rates rising on their own. That said, the bond market has been known to "go rogue" (see: vigilantes, bond market). Some might argue that the bond market has already gone rogue, albeit to the downside in yield. There is a good chance the high yield on the 10 year this year will be just 3 percent. Incredible.

Europe: hurt or help?

One reason rates remain so low is the renewed economic woe of Europe. The German economy contracted last quarter, and France and Italy remain fiscal wrecks. Those economies are roughly two-thirds of the entire euro zone economic output. The European Central Bank can't and likely won't sit idly by and watch these economies tumble without trying something.

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Whatever you want to call it — credit softening, quantitative easing, money printing, a hail mary, etc. — some form of stimulus is on the way. The question for American investors is which will matter more to our markets: any liquidity-driven stimulative push of the ECB … or a continued deflationary downward spiral for Europe's major economies slamming our exports and thus our biggest stocks.

Midterm election hangover?

Will the GOP take back the Senate? Will the Democrats regain seats in the House? What happens to the three empty seats in the lower chamber? Where's Waldo? So many political questions remain with just over two months to go until midterm elections voting day. Yet economically there seems to be just one question: will the election uncertainty and coming barrage of negative attack ads freeze the American consumer or investor? Uncertainty can often be the most dangerous fiscal emotion. And the only thing we can be certain of for the next 10 weeks is that it is going to be N-A-S-T-Y.

Another year without a correction?

The last time we had a really bad run for stocks, "Moves Like Jagger" by Maroon 5 was the hottest song in America (that's late 2011 for all you non-radio listeners.) Since then, it's been nearly nothing but up, up and away for stocks. Not only has the S&P 500 not had a technical correction (bigger than 10-percent drop) since then, but as you can see the drops we've had had have actually gotten smaller in both price and time. It's good news for your 401(k) but does make me just a touch uneasy. Pullbacks can be healthy. Let's see what September brings.

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Commentary by Brian Sullivan, co-host of CNBC's "Street Signs." Follow him on Twitter @SullyCNBC.