NEW YORK ( Real Money) -- With the Dow barely positive for the year and with the visions of previous spring swoons dancing in our heads, it might be worth a moment to figure out which stocks in the averages could take us down and whether it is reasonable to expect that they will.What we are fearing, obviously, is the 1,000 point bruising we got from Dow 10,700 in May of 2010 through the summer and the hideous 2,000 point May-until-October annihilation that 2011 gave us. The worries are justified. Europe's in collapse mode and all but Germany's well below our average's performance Incredibly, given its location, Germany's still up 5% from where the year began. Now, of course, any average can have a wholesale reversal. We are seeing from the dramatic underperformance in the master limited partnerships so far to date, 1,000 basis points in weakness vs. the benchmark S&P, that yield's not protecting jack right now. Or at least these yields aren't. We also know that the pull of the foreign markets can overwhelm even the best of the domestically-based Dow stocks, but the bounceback tends to be pretty pronounced in those stocks. So, with those caveats who can do the most damage in the Dow from here? Who would take the averages down another 10%, the big fear out there on top of the 700-odd points of decline we have already had from 13,300? Who is, for the purposes of this analysis, VULNERABLE? First would have to be the oils. Exxon ( XOM) is down 3% and Chevron ( CVX) is down 5% this year, and while Chevron at least gives you 3.5% yield protection the Exxon yield of 2.79% doesn't mean jack. This group is in freefall. I don't see it stopping yet because we seem to be replaying last year's decline. The good news, though, is that even with a 2011 perspective Chevron sold down to only $90. But the bad news, Exxon hit $67. I think Chevron could bang us until it yields 4%, still a little ways, but Exxon, which reported a disappointing quarter, could decline another 7-8% fairly easy. Call Exxon vulnerable.