This market resolves NO on or about January 1, 2050.

Meta comment: This is another "what is the risk free interest rate" market, but testing a very long time period.

Based on my calculations about loans, I think that there's still a big difference in opportunity cost between a 1-month investment and a 1-year investment, but there actually seems to be only a tiny difference in opportunity cost between a 1-year investment and a 10-year investment. (Assuming it's a small part of your portfolio so it doesn't contribute much to the loan cap). This is because the vast majority of your opportunity cost is incurred in the first few months - with 2% of your investment being loaned back to you every day, by 365 days less than 0.01% of your investment is still locked up in the market.

There's another interesting consideration which is how much the long time frame affects questions like whether you and/or Manifold will still be around, etc. (Note that even if I am hit by a bus, Manifold admins have stated and shown that they usually will resolve popular markets eventually if the author is not responsive.)