(a)
Appropriations or funds available to an Executive agency, except a Government controlled corporation, for pay of employees stationed outside the continental United States or in Alaska whose rates of basic pay are fixed by statute, are available for allowances to these employees. The allowance is based on—
(1)
living costs substantially higher than in the District of Columbia;
(2)
conditions of environment which differ substantially from conditions of environment in the continental United States and warrant an allowance as a recruitment incentive; or
(3)
both of these factors.
The allowance may not exceed 25 percent of the rate of basic pay. Except as otherwise specifically authorized by statute, the allowance is paid only in accordance with regulations prescribed by the President establishing the rates and defining the area, groups of positions, and classes of employees to which each rate applies. Notwithstanding any preceding provision of this subsection, the cost-of-living allowance rate based on paragraph (1) shall be the cost-of-living allowance rate in effect on the date of enactment of the Non-Foreign Area Retirement Equity Assurance Act of 2009, except as adjusted under subsection (c).