Why GSEs subordinated debt is auctioned higher than senior unsecured

https://www.creditsights.com/strategy/_hpc/_23/075023.htm?referringChannelPath=/strategy/ --squeeze play: fewer sub deliverables relative to the size of CDS: three for FRE and four for FAN --coupon play: both are guaranteed by government, trading price is a function of the coupon. Sub bonds have coupon levels resulting in higher dollar prices.