Fitch downgraded Deutsche Pfandbriefbank (pbb) mortgage Pfandbriefe from AA+ to AA, on stable outlook, on Friday before withdrawing its rating of the covered bonds and citing “below average” and “incorrect” data in its final rating action.

The issuer in August had requested the agency end its rating of the instruments.

The mortgage Pfandbriefe were placed on Rating Watch Negative (RWN) on 11 September when Fitch implemented its revised covered bond rating methodology incorporating Discontinuity Caps (D-Caps) for German issuers.

“Following the mortgage Pfandbriefe being placed on RWN, pbb confirmed to Fitch that it has no plans to change the programme in the short term to the extent that would allow an improved D-Cap assessment for the cover pool specific alternative management component,” said the rating agency on Friday.

Fitch said that the driver of the D-Cap is the “high risk” assessment for cover pool specific alternative management.

“Fitch considers the quality of the delivered portfolio data as below average,” it said. “As part of its reasonable investigation process, the agency found some of the data to be incorrect. Furthermore, certain data fields the agency typically receives could not be delivered.”

Given pbb’s long term issuer default rating (IDR) of A-, a D-Cap of 2 (high risk) limits the programme to an A+ rating on a probability of default basis and a AA rating considering recoveries given default, said Fitch, with the OC taken into account by Fitch (48.2%) sufficient to support the AA rating.

Pbb in February dropped Fitch from rating its public sector Pfandbriefe because it considered the overcollateralisation level required by the rating agency to maintain the covered bonds’ triple-A rating to be “not justifiable”. The rating was withdrawn after being cut from AAA to A+.

Pbb mortgage Pfandbriefe remain rated by Moody’s and Standard & Poor’s, with Aa1 (on review for downgrade) and AA+ (stable outlook) ratings. Its public sector Pfandbriefe are rated Aaa (on review for downgrade) and AA+ (stable outlook).