European stocks declined for a second day, extending a one-month low, amid speculation the Federal Reserve will scale back its debt-buying program.

In China, HSBC Holdings Plc and Markit Economics said their index of manufacturing in the world's second-largest economy fell to 49.2 in May from 50.4 in April. An official index for the industry, released on June 1, rose to 50.8 from 50.6.

National benchmark indexes retreated in 15 of the 17 western-European markets open today. The U.K.'s FTSE 100 slid 0.9 percent, while France's CAC 40 (CAC) dropped 0.7 percent. Germany's DAX lost 0.8 percent. Irish markets were closed for a public holiday.

Roche, the world's biggest maker of cancer drugs, slid 3.7 percent to 230.30 Swiss francs for the biggest decline since November 2011. Avastin failed to extend the survival of patients with deadly brain tumors in a study that found no advantage in using the drug as a first-line therapy against the cancer known as glioblastoma.

Munich Re, the world's biggest reinsurer, lost 2.7 percent to 140.80 euros and Hannover Re, the fourth-largest, dropped 3.3 percent to 56.39 euros.

Prague braced for the swollen Vltava River to crest today as the Czech government deployed hundreds of soldiers to avert a repeat of the 2002 floods that destroyed neighborhoods and caused $1.2 billion in damage. The German cities of Passau, about 30 miles from the Czech border, and Rosenheim declared a state of emergency and rivers in Saxony, Baden-Wuerttemberg and Bavaria burst their banks.

Ingenico SA, a French provider of payment terminals and services, decreased 3.4 percent to 50.92 euros for its biggest drop in three months. Berenberg Bank downgraded the stock to sell from hold, citing an increase in competition.