Good thing the U.S. stock market was off today. Shares around the world plummeted Monday over worries about the American economy and Europe’s sovereign-debt problems. The Euro Stoxx index plummeted 5.1 percent, while in Germany, the DAX fell 5.3 percent, with banks leading the decline. Royal Bank of Scotland lost more than 12 percent, and Deutsche Bank fell nearly 9 percent. Deutsche Bank AG Chief Executive Josef Ackermann said market conditions felt similar to those in 2008, when the world economy was on the brink of collapse. In Asia, the Hang Seng index in Hong Kong slid nearly 3 percent. The fall in overseas trading of stock index futures—the Dow Jones dropped 200 points—indicates that a selloff is likely Tuesday.