The TSP has released the following announcement:
The TSP has mailed IRS Form 1099-R, Distributions from Pensions, Annuities, Retirement or Profit-Sharing Plans, IRAs, Insurance Contracts, etc., to participants who received a withdrawal up to December 26, 2014, and/or a taxable distribution of a loan up to December 31, 2014. (Taxable distributions declared on December 29, 30, and 31 are taxable income for 2014.) If you have not received Form 1099-R by mid-February, you can print out a copy from My Account. Corrected Forms 1099-R will be issued late February/early March. If you are expecting a corrected Form 1099-R, you may wish to wait to file your taxes until you receive the form.