(33)Delegated Regulation (EU) 2015/35 does not distinguish between senior tranches and non-senior tranches of non-STS securitisations. That lack of risk-sensitivity results in overestimating the spread risks underlying investments in the highest-quality tranches of non-STS securitisation. In addition, the difference in capital requirements for insurance or reinsurance undertakings between STS and non-STS securitisations is much more significant than that applicable to credit institutions. Therefore, to preserve that difference, lower risk factors should be introduced for senior tranches of non-STS securitisations.