Stock markets are lower today on weaker-than-expected manufacturing data in the U.S. The ISM factory index fell to 51.3 in March from 54.2 in February. This still indicates expansion, but it's on the cusp of a negative reading. It was enough to get traders to day "Sell, sell, sell": and the Dow Jones Industrial Average (INDEX: ^DJI) is down 0.17% as of 3:20 p.m. EDT, while the broader S&P 500 (INDEX: ^GSPC) has fallen 0.64%.

Alcoa (NYSE: AA) and Caterpillar (NYSE: CAT) are down about 1.8% each on the manufacturing data. Both companies rely on economic growth, particularly in the manufacturing sector. The March reading was just one data point, and we're still seeing expansion, so there's no reason to panic just yet.

Intel (NASDAQ: INTC) has fallen 2.2% after analysts at JMP Securities downgraded the stock to "market perform." The analyst cited problems with the company's Haswell architecture and said they may lead to a technology change in Intel's power management scheme in the future. Intel is supposed to launch the new products at the end of this year, and investors are hoping it turns around the lackluster results of recent quarters.

On the positive side, AT&T is up 1.4% after authorizing a 300 million-share repurchase program. That's about 5.5% of the common shares outstanding, and there's no expiration date. Repurchasing is one of two ways companies can give cash back to shareholders' the other is through dividends, which AT&T pays each quarter. The theory is that earnings per share will rise because of the lower share count, pushing the stock higher, although history has shown that management has a poor track record of timing stock purchases.

Fool contributor Travis Hoium owns shares of Intel. The Motley Fool recommends Intel. The Motley Fool owns shares of Intel. 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.