The Financial Services Authority has fired a warning shot at banks thinking of paying their executives guaranteed bonuses that run for more than a year.

In a letter sent to more than 40 chief executives in the financial services sector, the head of the U.K. regulator, Hector Sants, cautioned that the offer of such a bonus “may be inconsistent with effective risk management.”

That was read as a warning to firms that they shouldn’t try to lure star performers from their rivals by offering guaranteed payouts before the FSA’s new code on remuneration takes effect later this year.

Sants also used the letter to tell firms that they must give the regulator a statement on their remuneration policy by the end of October. This must include all the information the FSA needs to check that pay policies and practices comply with its new code from January next year.