Soothing words from US Federal Reserve Chair Janet Yellen have helped pull the stock market out of a morning slump, but internet companies and Whole Foods Market plunged, taking the Nasdaq down.

As comebacks go, this one was a couple of days in the making.

Shares in Twitter have gone on sale to the public for the first time, instantly leaping more than 70% above their offering price in a dazzling debut that exceeded even Wall Street’s lofty hopes.

Trading in shares of more than 3,000 US companies listed by Nasdaq, including Google, Apple and Microsoft, was abruptly halted shortly after midday yesterday because of a technical problem, the latest black eye for the US securities trading business.

The stock market rose yesterday after two lacklustre economic reports convinced traders that the US central bank will continue to boost the economy with its stimulus programme.

Signs of a slowing economy combined with comments from a Federal Reserve official helped pull the US stock market down yesterday.

Strong housing and earnings reports helped US stocks rebound from their worst day of the year.

Stocks closed little changed on Wall Street last night as budget talks continued in Washington.

The stock market enjoyed some Black Friday cheer, rising sharply as shoppers braved the annual post-Thanksgiving rush. Major stock indexes closed one of their best weeks of the year.