Bank stocks have come to life recently. But Jim Cramer explains why the rally may not last

KeyCorp (KEY) reiterated its financials Tuesday, sending its shares higher — a rally that’s been seen in the wider financial sector recently. The stock, however, edged lower after Wednesday’s open on Wall Street. That’s because, according to Jim Cramer, investors are focusing their attention on big banks, rather than smaller regionals.

“There’s a big split right between investment banks, big money centers and the regionals,” Cramer said, cautioning that the recent banking sector rally may not be sustainable.

Wells Fargo (WFC) and Morgan Stanley (MS) — two holdings of Cramer’s Charitable Trust, the portfolio used by the CNBC Investing Club — have notched gains in recent sessions as well following a challenging year amid a crisis of confidence in the entire industry after the March failure of Silicon Valley Bank.