(Adds details about ratios at UBS, Credit Suisse)
ZURICH, June 21 (Reuters) - Switzerland's two biggest banks, UBS and Credit Suisse, have more work to do on emergency planning to meet new too-big-to-fail rules by the end of 2019, the Swiss National Bank said on Thursday.
"Since publication of the last Financial Stability Report, the two Swiss big banks have further improved their compliance," the central bank said in its 2018 financial stability report. "However, progress is still necessary, particularly as regards resolution planning."
The banks have until the end of next year to prepare so-called resolution plans that would prevent taxpayers from having to bail them out in the event of a crisis.
Both banks are on track to meet updated too-big-to-fail (TBTF) capital requirements, the SNB said, but must improve their leverage ratios, or the ratio of core capital to total assets.
Under the new rules, UBS and Credit Suisse will need to hold core capital representing 5 percent of total assets, known as the leverage ratio. At least 3.5 percent of that should be high-quality common equity tier 1 (CET1) capital.
They will also need to meet a high-quality common equity tier 1 ratio of 10 percent.
Credit Suisse had a CET1 ratio of 12.9 percent and a CET1 leverage ratio of 3.8 percent in the first-quarter, compared to a CET1 ratio of 13.1 percent and a CET1 leverage ratio of 3.76 percent at UBS.
Both banks saw their CET1 ratios drop in the first quarter due to regulatory adjustments in the calculation of risk-weighted assets. (Reporting by Brenna Hughes Neghaiwi, editing by John Miller)