The Bull and Bear sculptures outside the Frankfurt Stock Exchange Xinhua/Getty Images European shares eased, but would still likely post their biggest monthly increase on record in November, buoyed by optimism over the economic outlook from the rollout of a COVID-19 vaccine. Market-based signs of investor nervousness, including falling government bond yields and a rise in volatility, pointed to a degree of caution over the coming weeks. "Even with so many very positive signs on vaccines, it will be months before these facilitate a return to greater activity levels," ADM Investor Services chief global economist Marc Ostwald said. Visit Business Insider's homepage for more stories. European shares retreated on Monday, but the region's benchmark index was still set for its biggest ever monthly rise, as optimism over a vaccine has helped lift some of the most battered sectors in one of the virus hotspots.The Stoxx 600 fell by 0.1% in early trading, under pressure from profit-taking in some of the "real-economy" sectors, such as energy, banks and retail.