The Sensex was up by over 581 points ahead of the close of trade today as investors cheered the government's pledge to trim its Budget shortfall and boost spending on projects needed to sustain growth and contain inflation. The 30-share index of the Bombay Stock Exchange, which rose by nearly 200 points in the previous two trading session, was up by 581 points at 18,404 points. Similarly, the broad-based National Stock Exchange index Nifty was up by 177 points at 5,510 points at the same time following a surge in stocks of auto, capital goods and banking firms.