S.D. Codified Laws § 3-12C-1301
Each generational member shall have a variable retirement account, which consists of variable retirement contributions and the credited investment return. The investment return shall be credited annually as of June thirtieth for all generational members with a variable retirement account on that date. The credited investment return is the South Dakota Investment Council's reported money-weighted investment return of the system, net of fees, for the completed fiscal year. In the case of a distribution during the fiscal year, the credited investment return is the estimated investment return to the end of the month before payment. Any variable retirement contributions made during the fiscal year shall receive one-half year's credited investment return.
SDCL 3-12C-1301