Deriv1.com data show regular spreads between the GCF Repo Index® and individual US Treasury repo tenors to be 4-10 basis points. With spreads this large in a leveraged product, why hasn’t an enterprising trader picked up the profit?

Deriv1.com data show regular spreads between the GCF Repo Index® and individual US Treasury repo tenors to be 4-10 basis points. With spreads this large in a leveraged product, why hasn’t an enterprising trader picked up the profit?