Ok, certamente é preciso ver aquela queda ali, linear, na segunda parte do gráfico, mas isto pode ser feito por um bom analista (como o Thomaz, por exemplo). Mas o gráfico conta uma história bem simples, né? A descrição da série:
Petroleo Brasileiro Petrobras SA (ADR) (PBR)
Desc: Petroleo Brasileiro SA Petrobras (Petrobras) is a Brazil-based integrated oil and gas company. The Company divides its activities into seven segments: Exploration and Production; Refining, Transportation and Marketing; Gas and Power; Biofuel; Distribution and International. Directly or through its subsidiaries, Petrobras is engaged in the research, extraction, refining, processing, trade and transport of oil from wells, shale and other rocks, its derivatives, natural gas and other liquid hydrocarbons, as well as in activities related to energy, development, production, transport, distribution and commercialization of energy. The Company’s offering comprises road transportation products such as Automotive Gasoline, Diesel Fuel, Natural Vehicular Gas, Lubrax; agriculture and cattle raising products such as Sunflower Meal, among others; Industrial products such as Solvents and Paraffins, among others. The Company provides its services both for individual and business clients.
Pronto, agora você já tem outro motivo para aprender a trabalhar no R (e com o pacote Quandl).