Two activist hedge funds say the time for TD Ameritrade ( AMTD - Get Report) to sell itself is now.

The funds, S.A.C. Capital Advisors and Jana Partners, have taken an 8.4% stake in the Omaha, Neb., online broker. They called Friday for the second time in a week on Ameritrade to sell itself to either Charles Schwab ( SCHW - Get Report) or E*Trade Financial ( ETFC - Get Report).

"Quite frankly, we fail to see how an unbiased review could leave any doubt that the 'right time' to pursue such a combination is now," the hedge funds say in a letter to Ameritrade and accompanying press release. "This is particularly true given that the company has now completed its integration of TD Waterhouse and that the currently favorable industry environment for transactions will most assuredly not last forever, creating the real risk that if the board continues to wait it will have permanently squandered this opportunity."

The comments from S.A.C. and Jana come a day after Ameritrade chief Joe Moglia told investors that the company would be "deliberate" in pursuing its growth strategy.

Shares of all three online brokers rose on the news. TD Ameritrade's stock rose 41 cents, or 2%, to $20.41. Shares of E*Trade rose 37 cents, or 1.5%, to $24.55. Schwab, which has said it's not interested in buying Ameritrade, rose 10 cents to $21.32.

S.A.C. and Jana first suggested Tuesday that TD Ameritrade "pursue a business combination with one of its industry peers."

In Friday's letter, S.A.C. and Jana also reiterated that they see "glaring conflicts of interest" in TD Ameritrade's dealings with its largest shareholder, TD Bank ( TD - Get Report). The funds say TD Bank won't pursue a sale of Ameritrade because of "its reliance on the company to advance its own business strategy."

They suggested that TD Ameritrade use a committee of outside directors that is "free from influence" of TD Bank to review possible merger considerations.

Moglia said Thursday at a Sandler O'Neill & Partners Conference that the company regularly reviews its M&A strategy and cautioned that investors should not limit the company's next acquisition to just an online broker.

The company has "an intense focus on our business plan and along with that really looking hard to make sure we are looking at a number of opportunities in the marketplace -- not just what's going on in online brokerage," Moglia said. "As we get more into the asset gathering space perhaps we're supposed to be more creative with regard to where we might look for strategic opportunities."