An option for retirees to start collecting Social Security at age 62 or later at that lower rate, then cancel at age 70, repay all collected but WITHOUT interest (amounting to a free loan), and then file anew for Social Security at the higher rates for starting at age 70 has just be stopped by the Social Security Administration.
That practice is no longer allowed as of two days ago, Dec. 8. social-security-payback-option-eliminated: Personal Finance News from Yahoo! Finance
The benefit in doing this was that you would get to keep any interest and investment earnings from that money, and from age 70 and up collect the higher amount. This typically would be an approach taken only by wealthier recipients.
I note, the article does not mention whether this bars people who already had started this approach in the last few years but have not yet reached age 70 to do the payback and restart, leaving them stuck at the lower rate they never intended. But I suspect it will bar them from doing so -- which certainly would have to leave them shell shocked.