This market is designed as an experiment to see whether manifold odds will match the real stock market, or if it behaves more like a betting market. According to the 3 year gov bond rate, if you bought $412 worth of bonds right now, you would have $457 at this time in 3 years. Adjusted for the payouts you would recieve if you held spy, this difference results in the number in the title (436). Therefore, if people are able to hedge against the real stock market, the value of this market should start at about 50/50. However, it is very likely that this market resolves yes due to SPY's tendency to outpreform government bonds.