With the financial sector on a tear, we could be at the start of a "stealth rally," CNBC's Jim Cramer told "Squawk on the Street" on Wednesday.

"I think this is another stealth rally — no one's talking about it," Cramer said. "People want to get out of these stocks. You gotta stay in. This is day one of the rally."

A fund that tracks the financials sector bounced 1 percent Wednesday, with Wells Fargo shares gaining 3 percent after the debut of their new mobile wallet platform.