My guess is that Amex paid SPG about 1400-1500 for 140K spg.

SPG paid US .75 x 175,000 or $1375.

US paid $2000 or maybe less for the 2 F tickets.

I'm guessing that AMex pays in the 1% area as that is a common cashback number and SPG probably is one of the more expensive points. I'm guessing that when you convert SPG to airline the don't make much but don't lose much either. I'm thinking that US lost money on this but that generally they do make money overall as some miles never get redeemed or redeemed for cheaper awards.

Remember that Swiss can use capacity control and therefore are only going to give award seats when they are 99% sure that the seat will not be sold. I think they get a fraction of retail price. Also note that F seats are only twice the mileage of Y seats so I am betting that the cost to US is only about twice as high. Considering that airlines are generally more willing to sell the cheapest coach seat more often than an award seat you can bet they get less for the coach award then the cheapest coach fare.

If I had to guess, I'd say a partner gets 50-70% of the lowest coach fare and an F seat is double that number.