As 2020 accounts trickle in for the Irish subsidiaries of US vulture fund Cerberus, a pattern is emerging.  After Covid-19 hit last year, all these tax-efficient special-purpose vehicles have so far reported a slowdown in debt collections on the portfolios they acquired here after the financial crisis. Some are moderately affected, such as Promontoria Gem, which bought a bundle of residential and commercial property loans in Ireland and the UK from Nama in 2017. At the time, it valued this asset at €361 million and immediately started collecting this debt from borrowers. Of the €68 million valuation remaining at the…