Once again, the Dow Jones Industrial Average (DJINDICES:^DJI) is pushing higher today. As of 12:55 p.m. EDT, the index has added 64 points, or 0.44%. It's poised not only to set a new record closing high, but also to stretch its winning streak to 10 days.

The markets in general are moving higher today. The S&P 500 has gained another 0.41%, leaving it just four points away from its all-time high of 1,565, while the NASDAQ is higher by 0.33%. But even as the markets move closer to setting new highs, a few losers are attempting to hold the indexes back.

Today's Dow downers
Shares of Merck (NYSE:MRK) have fallen 1% today after new reports indicated that the U.S. Food and Drug Administration is reviewing documents connecting Merck's Januvia drug to serious health issues. The study from JAMA Internal Medicine claims to have found a link between certain diabetes medications, including Januvia, and increased pancreatic problems. The FDA's looking into how JAMA collected the data and what led the study's authors to their conclusion.

At this time, the FDA has not given any official statement on whether Januvia is harmful or not. But if officials find the drug does cause further harm, it may be taken off the market. At the very least, it could come with much more severe side-effect warnings, which would likely lead doctors to prescribe it less frequently.

In the world of retail, shares of Wal-Mart (NYSE:WMT) are down 0.4%. The company relies on shoppers receiving and spending their tax refunds during this time of year, and so far 2013 has not been good for refunds.

First, the IRS pushed the earliest possible filing day back by more than a week because of tax code changes resulting from the fiscal-cliff compromise. In February, those claiming earned-income tax credits were hit by refund delays. Now the IRS is claiming that refunds for more than 6000,000 taxpayers who claim an education credit will be delayed for up to six weeks.

On Tuesday a Wal-Mart executive said customers had cashed in refund checks worth $2.7 billion. But at this time last year, the company had processed about $4 billion worth of refund checks, much of which was later spent in its big-box stores.

Lastly, Caterpillar (NYSE:CAT) is trading lower by 0.6% following reports that company employees in Europe are protesting against recent moves to cut its European workforce. The EU's manufacturing industry has struggled since the recession hit. Combine industry layoffs and wage cutbacks with the austerity programs many EU countries have been forced into, and it's easy to see how further job cuts could set off protests and, possibly, strikes. If the company is hit with a strike, both its short-term and long-term costs will likely climb, lowering its profits.

Fool contributor Matt Thalmanhas no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Check back Monday thru Friday as Matt explains what caused the Dow's winners and losers of the day, and every Saturday for a weekly recap. Follow Matt on Twitter @mthalman5513. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.