How wide would the BTP/Bund yield spread be without the ECB’s intervention?

The ECB’s interventions (government bond purchases, pushing investors into riskier bonds such as Italy’s by leading to very low risk-free interest rates; the ability to overweight purchases of Italian bonds under the PEPP) have led to a tightening of the long-term yield spread between Italy and Germany (there is talk of “spread control” by the ECB). Given the public debt ratio, the potential growth gap between Italy and Germany and the gap between the ir current account balances, we seek to determine what the 10-year yield spread between Italy and Germany (the 10-year BTP/Bund spread) would be today without the ECB’s intervention ( the entire public debt would be held by private investors). A statistical analysis suggests that without the ECB’s intervention, today’s Italy / Germany yield spread would be 400 basis points, compared with around 170 basis points for the actual spread.