The name you choose is up to you, provided you do not impersonate anyone or use offensive language. Some commenters use their real names, others choose a pseudonym to maintain anonymity.
Should you choose a pseudonym, we recommend that you choose a distinct one. If it transpires that you have chosen the same pseudonym as someone else, an FT administrator may email you to inform you and require you to change your name. Using offensive language in your pseudonym may lead to a temporary ban until your pseudonym is changed. Do note that all comments made under a pseudonym can be tracked back to your FT.com account.