GLOBAL MARKETS-Global stocks, dollar slide on recovery fears

* U.S. stocks slide as economic data curbs optimism

* S&P lower outlook for UK stirs fears about U.S. debt

* German bunds shine as gilts wilt after S&P action

* Dollar slumps, sterling falls, then rises on S&P

* Oil falls below $61 after rise to 6-month peak (Updates with U.S. markets activity; changes dateline, previous LONDON)

By Herbert Lash

NEW YORK, May 21 (Reuters) - Global stocks slid, the dollar fell and U.S. government debt plunged on Thursday as fresh signs of economic weakness and a potential credit rating cut for Britain dashed budding hopes for a quick recovery.

U.S. Treasuries debt fell sharply after the government said it would sell $101 billion of new notes next week, adding to worries whether global investors can digest all the pending supply.

Bond investors were also left mulling the value of U.S. debt after Standard & Poor's cut its credit outlook on the United Kingdom to negative from stable.