Everyone brace yourselves because the broad-based S&P 500 (^GSPC -0.22%) is set to end the week down for the first time in a month. A mixture of profit-taking and concern that the Federal Reserve may wind down its bond-buying program sooner than expected has investors spooked.

The Fed's bond purchases create a sort of catch-22 for investors. On one hand, winding down its purchases would signal strength in the U.S. economy and point to it becoming more self-sufficient. Alternatively, fewer bond purchases could potentially move lending rates higher even with the Fed targeting record-low lending rates through 2015. In short, investor uncertainty has yielded another choppy, but modestly lower, reaction in the S&P 500.

When all was said and done, the S&P 500 ended lower by 0.91 points (-0.06%) to close at 1,649.60. There were few catalysts to send the market higher today, but the following three stocks certainly found the will to buck the downtrend in a big way.

Ascending to the top of the pack was robotic surgical device maker Intuitive Surgical (ISRG -0.41%), which gained 4.8% after winning a lawsuit involving its da Vinci surgical system. The plaintiff in the case was a family that sued for $4.9 million following complications from a 14-hour prostate cancer surgery. The jury's verdict isn't too important from a monetary perspective for Intuitive so much as it reinforces the safety of its surgical devices, which are currently under investigation by the federal regulators. I certainly feel there could be further upside in Intuitive shares from here.

The world's largest consumer products maker, Procter & Gamble (PG 0.86%), surged higher by 4% after announcing that Bob McDonald was retiring as CEO. More interestingly, former CEO A.G. Lafley, who was head of P&G from 2000 to 2009, has rejoined the company as its new CEO. Lafley was responsible for steadily growing P&G's core brands during his tenure, so shareholders seem very pleased to have him back. I can't help but be a bit excited as well because P&G's huge advertising campaign really hasn't hit home with consumers as of yet. I'd suspect the readdition of Lafley could move the company's marketing in a completely different direction, which would ultimately be beneficial to its bottom line.

Finally, advertising and marketing services company Omnicom Group (OMC -1.03%) added 3.4% despite no company-specific news today. However, earlier in the week, Omnicom announcement that it was keeping its dividend steady at $0.40 in the upcoming quarter certainly invigorated shareholders, who are digging Omnicom's 2.5% yield. Personally, I can't help but be a little skeptical of ad and marketing consultants in a slow-growing global environment, but shareholders are definitely enjoying a solid end to the week.