Can I obtain a security clearance on my own?

How to obtain a security clearance.

No. You must be sponsored by a cleared contractor or a Government agency. To be sponsored you must be employed (or hired as a consultant) in a position that requires a security clearance. As an exception, a candidate for employment may be submitted for a security clearance if the employer has made an offer of employment and the candidate has accepted the offer. Both the offer and acceptance must be in writing. The offer of employment from a cleared contractor must indicate that employment will begin within 30 days of receiving the security clearance.