Fantex, a brokerage firm based in San Francisco, soon will begin a campaign to sell shares of Buffalo Bills quarterback EJ Manuel on the stock market.

Manuel signed a "brand contract" with the company in February, becoming one of the first athletes to receive an up-front payment from the firm in exchange for a stake of his future income. Fantex is expected to announce Thursday when Manuel's stock, which will trade under the ticker symbol EJMLL, will begin trading publicly.

Fantex will offer 523,700 shares of Manuel stock at $10 per share. The company will pay $4.97 million to Manuel for a 10 percent interest in his "brand income," which includes his contract, endorsements, and any post-career income such as a broadcasting deal. Fantex's prospectus for Manuel's stock estimates that the quarterback will earn $104 million during and after his career.