An activist group (is) buying and cancelling other people's student debts. Rolling Jubilee has purchased and abolished $3.8m (2.35m) of debt owed by 2,700 students. Debts can be bought and sold in the financial marketplace. But student debt, which has spiralled to an estimated $1.2 trillion (619bn), is not usually as available to buy as other debts. In this speculative secondary market, third parties buy debt for a fraction of its original cost. These debt campaigners are buying debts and then writing them off. Laura Hanna at Rolling Jubilee says, We wanted to question the morality around repayment. Your debts are on sale. They are just not on sale to you." Ms Hanna says ... the way that selling education as a commodity reinforces inequality. The group is hoping to show students that if they work together, they can renegotiate their debt. Student debt can pursue people all through their working lives and into retirement. Officials giving evidence to a US Senate committee said this could mean that student debt repayments could be deducted from retired people's social security benefits. John Aspray, national field director at the United States Student Association (USSA), said recent changes in law mean people in medical or gambling debt can declare themselves bankrupt - but to do so for student debt ... is very difficult. "Opportunities for renegotiating are very well hidden."