NEW YORK, Jan 4 (Reuters) - Hedge fund manager Bridgewater Associates' flagship Pure Alpha fund lost 7.6% last year, a source familiar with the matter said on Thursday.

The performance came amid a rally in U.S. stocks, with the S&P 500 index up roughly 24%, while bonds yields spiked.

The Pure Alpha 18% volatility fund, however, is structured in a way to have no bias with markets ups and downs, the source said.

All Weather, a Bridgewater fund that is designed to follow markets more closely, rose 10.6% last year, the person added.

Reuters reported in August that Pure Alpha had a

"moderated" bearish

view on U.S. stocks, but it is not clear if the fund changed its positioning later or ended up not catching the year-end stock rally.

Bridgewater, whose founder Ray Dalio is co-chair and co-chief investment officer, declined to comment on the matter.

Bloomberg reported earlier on Thursday on Bridgewater's funds performance. (Reporting by Carolina Mandl in New York Editing by Chris Reese and Leslie Adler)