I'm reading a book about bonds, but the book doesn't explain one of the questions I want to know, why is FGBL's basis so large to spot? Looking at the FGBL that expired in March, the market price is 170.96, but the spot price is only 100.72, and the futures price is a full 69.7% higher than the spot price, but there is no arbitrage. The book I read only talks about U.S. Treasuries, and there is no analysis of European markets.

I found FGBL's CF elsewhere, problem solved