NEW YORK (AP) — Individual primary-dealer banks can now borrow as much as $4 billion in securities from the Federal Reserve, up from the previous limit of $3 billion, the central bank said on its Web site Tuesday.

Raising the lending ceiling is the latest change to the Fed's securities lending program, whose rules have been relaxed over the past year to minimize the number of trade delivery failures. A delivery failure is, essentially, when a borrower cannot meet its obligation on time.

It's a fairly normal occurrence, but the number of delivery failures is expected to have spiked over the past week, as the credit crisis effectively obliterated the U.S. investment banking industry. The Fed is scheduled to release its weekly data on trade failures late Thursday.

The change Tuesday was not as monumental as some of the others made by the Fed to keep the markets functioning, such as facilities announced in March to allow securities dealers to get Treasurys at auction for 28 days and for securities firms to receive overnight loans.

"It's one more incremental measure among many to address financial market stress," said Michael Feroli, an economist at JP Morgan Chase. "I don't think it's going to end the credit crisis, but at the margins, it should help to relieve the stress in one corner of the many markets that are stressed."

There are about 17 primary dealers that borrow securities from the Fed. These banks include JPMorgan Chase & Co., Citigroup Inc., Bank of America Corp., Merrill Lynch & Co., and Goldman Sachs Group Inc. Lehman Brothers Holdings Inc., which filed for bankruptcy on Sept. 15, was deleted from the list as of Monday.