NEW YORK (Bloomberg) — Syncora Holdings Ltd.'s bond insurance unit, seeking to restructure guarantees on mortgage-backed securities, had its financial strength rating cut to below investment grade by Standard & Poor's.

Syncora Guarantee Inc.'s rating was lowered five steps to B from BBB- and remains under review for additional downgrades, New York-based S&P said in a statement yesterday. S&P cited Syncora's delay in implementing its restructuring plan and slow progress in its negotiations with counterparties of its collateralised debt obligation of asset-backed securities exposure.