As of May 2024, the nearest known black hole to Earth is Gaia BH1 at 1560±10 light years. However this and the next three black holes by distance have all been discovered since 2022, so it is likely that newer even closer black holes will be discovered in the foreseeable future.

It is also possible that new types of black holes might be discovered, such as primordial black holes with masses much lower than that of stellar black holes.

If no exotic tiny black holes are discovered, the market is resolved based on the nearest black hole listed on the List of nearest known black holes Wikipedia page.

If some new types of black holes are found and it is proven that they appear in the Solar system, the market resolves to 0. The black holes in questions have to be stable with the lifetime of at least 1 second, so if it turns out that Planck scale black holes come into existence and vanish due to some quantum fluctuations, they will not count.

The market is resolved based on the nearest black hole on January 1st 2030.

I do not bet on my own questions.