* MSCI world shares index up 0.5% * GameStop’s Frankfurt-listed shares down 30% * Silver tumbles further from 8-year high * Biden set to debate Republicans on stimulus package * Euro at 7-week lows on economic outlook LONDON Feb 2 (Reuters) - Global stock markets gained for a second day on Tuesday, spurred by increased optimism about economic stimulus and global recovery, while retail investors retreated from GameStop and their new-found interest in silver. Positive momentum from Asia carried through to Europe, with the pan-European STOXX 600 edging up 0.9%. Shares in BP lost 3.8% after it plunged to a $5.7 billion loss last year, its first in a decade. ADVERTISEMENT MSCI’s world equity index, which tracks shares in 49 countries, was 0.4% firmer after posting its strongest day in three months on Monday. MSCI’s gauge of Asia Pacific stocks outside Japan rose 1.5%, with China’s benchmark CSI300 Index climbing 1.5%, helped by easing concerns about tight liquidity and falling cases of new coronavirus infections. Japan’s Nikkei 225 added 1%. E-mini futures for the S&P 500 index added 0.8%. Markets were buoyant ahead of negotiations Tuesday between U.S. President Joe Biden and Republican senators on a new COVID support bill. The GOP’s $618bn stimulus plan released early Monday was about a third the size of the President’s proposal. Top Democrats later on Monday filed a joint $1.9 trillion budget measure in a step toward bypassing Republicans. “If you have the ability to have stimulus compromise it’s going to be very supportive for financial assets in the medium term as it means you will have the ability to have an economic recovery,” said Francois Savary, chief investment officer at Swiss wealth manager Prime Partners. “The $1.9 trillion was set as a high bar of the possibilities and in a way to get into a negotiation to get something that would be smaller and more efficient.” The dollar hovered near a seven-week high, benefiting from a euro selloff overnight after coronavirus lockdowns choked consumer spending in Germany, and on short-covering in over-crowded dollar-selling positions. The dollar index eased a touch by 0.1% to 90.91. Against the U.S. dollar, the euro was trading at $1.2078, just above an early December low of $1.2056 hit in the previous session. ADVERTISEMENT The Australian dollar pared gains after the country’s central bank said it will extend its quantitative easing programme to buy an additional $100 billion of bonds. The Aussie last stood at $0.7627, nearly flat on the day. Turkey’s lira firmed more than 1%, extending a rally after the central bank promised tight policy for an extended period last week. With global market sentiment remaining upbeat about U.S. fiscal stimulus, core euro zone government bond yields edged up, with the benchmark German 10-year Bund yield < DE10YT=RR.> around two basis points higher at -0.4980%. Institutional investors are still digesting the retail trading frenzy that boosted GameStop Corp and other so-called meme stocks in recent sessions against their financial fundamentals but have made cautious moves to protect their positions. GameStop’s Frankfurt-listed shares were down 30% from Monday’s close at 143 euros in early trade on Tuesday. It closed in U.S. markets at $225. Spot silver prices slipped 4.8% to $27.59 per ounce, as investors locked in profits after the precious metal touched a near eight-year peak in the previous session driven by retail investors. Spot gold fell 0.6% Tuesday to $1,847.51 per ounce. Brent crude was up 1.1% at $56.95 a barrel. U.S. crude gained 1.2% to $54.22 as falling inventories and rising fuel demand due to a massive snow storm in the Northeast United States propped up prices. Editing by Richard Pullin and Giles Elgood Our Standards: The Thomson Reuters Trust Principles.