user: What is the best-selling single worldwide?

assistant: The best-selling single worldwide, according to Guinness World Records, is Irving Berlin's "White Christmas", which was performed by Bing Crosby in 1942 with over 50 million copies sold.

user: Are Schindler elevators safe

assistant: Schindler Holding Ltd. is a Swiss multinational company which manufactures escalators, moving walkways, and elevators worldwide, founded in Switzerland in 1874. Schindler produces, installs, maintains and modernizes lifts and escalators in many types of buildings including residential, commercial and high-rise buildings.

The company is present in over 140 countries and employs more than 66,000 people worldwide. The production facilities are located in Brazil, China, Slovakia, Spain, Switzerland, India and the United States. All operations and subsidiaries of Schindler Group are organised into Schindler Holding Ltd., which is publicly traded on SIX Swiss Exchange.

user: What is a hedge in finance?

assistant: A hedge is an investment position intended to offset potential losses or gains that may be incurred by a companion investment. A hedge can be constructed from many types of financial instruments, including stocks, exchange-traded funds, insurance, forward contracts, swaps, options, gambles, many types of over-the-counter and derivative products, and futures contracts.