Federal Reserve Chairman Jerome Powell said the central bank has been looking at long-term options to improve market liquidity, including “intraday liquidity” measures, after short-term markets suffered an alarming funding squeeze last month.

The Fed is considering technical adjustments to head off a repeat of the September liquidity crunch, Powell said at a news conference Wednesday. He said he doesn’t think the agency will consider changes to Wall Street’s capital or liquidity rules.

“It used to be a common thing for banks to have intraday liquidity from the Fed, what we called daylight overdrafts,” Powell said. “That’s something we can look at, and there are some technical things we can look at that would perhaps make the liquidity that we have -- which we think is ample -- in the financial system move more freely.”

The Fed in recent decades has placed increasing limits on the ability of banks to overdraw their accounts, as might happen in the course of large transactions throughout the day.

Powell said the Fed was surprised by the behavior of the megabanks last month. The Fed had surveyed banks to find out the liquidity minimums they were comfortable with, but Powell said they stayed far above those thresholds instead of putting that liquidity to a more lucrative use.

“They didn’t deploy that liquidity when there seemed to be great opportunities to do that,” he said. “So why is that? We’re doing careful analysis.”