Stocks posted modest gains Tuesday as investors worked through another large batch of earnings reports. Pharmaceutical stocks rose after drug giant Merck reported better-than-expected results. Twitter plunged nearly 20 percent after its results, which were released unexpectedly early, missed analysts' marks.

On Tuesday:

The Dow Jones industrial average rose 72.17 points, or 0.4 percent, to close at 18,110.14.

The Standard & Poor's 500 index added 5.84 points, or 0.3 percent, to 2,114.76.

The Nasdaq fell 4.82 points, or 0.1 percent, to 5,055.42.

For the week:

The Dow is up 30 points, or 0.2 percent.

The S&P 500 is down 2.93 points, or 0.1 percent.

The Nasdaq is down 36.66 points, or 0.7 percent.

For the year:

The Dow is up 287.07 points, or 1.6 percent.

The S&P 500 index is up 55.86 points, or 2.7 percent.

The Nasdaq is up 319.37 points, or 6.7 percent.