NEW YORK — You know things have changed on Wall Street when the housing industry saves the day.

A surprise government report that home construction picked up in February caught traders off guard and injected a week-old stock market rally with new energy yesterday.

Stocks of homebuilders and banks jumped as bullish investors saw yet another sign that the deeply troubled economy was beginning to show signs of stabilizing.

The housing report was the latest checkmark in a growing list of upbeat news. Traders began reconsidering their dire view of the economy early last week when Citigroup Inc. said it had generated a profit in the first two months of the year.