Confused by Gas Pricing

The pricing of Gas is confusing. According to the website UK National Gas Future, the wholesale price for Winter 2020 was 1.68p per kw at the beginning of 2018. It’s now 1.93p per kw. An increase of 0.25p per kw.
The price I pay has gone from 2.67p to 3.92p. An increase of 1.25p. So Bulb (and everyone else) have added 5 times the wholesale price increase.
So either:

  1. They were losing money at the old rate.
  2. Distribution costs have gone up massively.
  3. Suppliers are making a killing.
  4. I’m missing something.

https://www.theice.com/products/910/UK-Natural-Gas-Futures/data?marketId=5032602&span=3

Ideas anyone?