Dell has filed to take SecureWorks public, a move that's been rumored since before Dell agreed to acquire EMC.

The SEC filing for SecureWorks' IPO arrived Thursday afternoon, following up a confidential filing that had come in October. So far, the filing doesn't include details such as how many shares are being offered.

Rumors of a SecureWorks IPO surfaced in July at the Atlanta Business Chronicle, which quoted 451 Research in saying Dell was preparing to sell one-third of SecureWorks in an IPO.

That story said SecureWorks could be valued at more than $1 billion. An October story in The Wall Street Journal upped that figure to $2 billion.

In July, the rationale for taking SecureWorks public was simply to bring capital into Dell. That motivation still holds, but with renewed urgency; Dell now needs to shore up its finances for the pending $67 billion acquisition of EMC.

Moreover, SecureWorks competes with RSA, which is part of the EMC Federation of subsidiaries.

Dell (Probably) Keeps Control

SecureWorks was acquired by Dell in 2011 for $612 million, and it became a wholly owned subsidiary of Denali Holdings — Dell's parent company — when Dell was taken private in 2013.

Denali will continue to hold a stake in SecureWorks, and probably a controlling stake at that. While the percentages aren't in the S-1, there's a statement saying Denali's shares — designated Class B — will be worth 10 votes apiece. Buyers in the IPO will be getting Class A shares worth one vote apiece.

It's not just a power trip. Denali has to retain 80 percent of SecureWorks' shareholder voting power if it wants any eventual spinoff of the business to be tax-free, according to the SEC filing.

SecureWorks is still losing money. For its third quarter, which ended Oct. 30, the company reported a net loss of $18.5 million on revenues of $88.2 million, compared with a loss of $8.8 million on revenues of $66.8 million for the same quarter a year ago.

SecureWorks had 2,013 full-time employees at the end of October.

SecureWorks isn't Dell's only security play. The company acquired SonicWall in 2012 for an undisclosed amount. SonicWall's portfolio got a few enhancements at Dell World in October.