Anxiety intensified Friday about the toll the sub-prime mortgage meltdown is taking on the financial industry at large, as Bear Stearns Cos. pledged to lend $3.2 billion to rescue a hedge fund battered by rising defaults on home loans. The jitters sent stocks tumbling across the board. “We know that these holdings are not unique to Bear Stearns,” said Drexel University professor Joseph R. Mason, co-author of a recent study warning of dangers in securities backed by home loans to high-risk borrowers. “It would be hard to find a Wall Street firm that hasn’t created similar funds.”