Hoping to take over the vacant position of Chunagon (vice-councilor of state), he told Tadanobu not to apply for a promotion in advance, but was defeated when FUJIWARA no Michinaga, who doubted Sanenobu's competence, backed up Tadanobu's appointment as Chunagon.
欠員ができた中納言への昇格を望み、あらかじめ斉信に対し自分を出し抜いて昇任申請をしないよう言い含めるが、誠信の能力に疑問を抱く藤原道長の後押しを受けた斉信が中納言に任ぜられた。