In response to your question: In the seasonal spread of October 6145 August-February, the spread has a negative value equal to approximately -11 today, while in the graph shown, the value of the spread is positive 11. How is it possible?

Spread trading can be a little more complex than outright trading. Not necessarily the trading aspects, but the charting. This is because of the long and short multiple contracts at the same time. Another issue related to your question is that there is no industry standard way of posting a spread position. MRCI spreads are seasonal - driven by the time of year and seasonal patterns, not necessarily the spread price.

The lean hog spread you’re referring to could be plotted in two ways:

1. Some traders would list the spread with the nearest month first each time. Example, HEG26:HEQ26. If they are long in the near month and short in the distant month, they are said to be “buying” the spread. If they are short the near month and long the distant month, they are said to be “selling” the spread. The MRCI lean hog spread is selling the near month and buying the distant month. In essence, they are selling the spread. Posting the spread in this format, the trader would subtract the Q26 from the G26 ( G26 91.650 – Q26 101.625 = -9.975). Setting your charts up in this format, and you sold the spread, the price must trend down to be profitable.
2. Other traders, and MRCI, have elected to post the contract you are buying first. The lean hog spread is then charted as HEQ26:HEG26. When the software subtracts the prices, it looks like this: Q26 101.625 – G26 91.650 = +9.975. Setting the charts up this way and the prices trending up means you are profitable. Most speculators are familiar with rising trends being profitable if they are long and falling trends being profitable if short the market. This is one of the reasons some traders decide to use this method for spread trade charts.

As spread traders, we must determine whether we sell or buy the spread. Once we know that, we can elect to use either charting style. Remember, the trends and possibly the spread values, whether negative or positive, are different depending on our style.  

If you follow MRCI charts while in the lean hog spread, even though the value is positive, you are profitable if the trend goes up and the number gets more positive.