(Corrects spelling of Credit Suisse in headline)
* Swiss finance minister floats harsher leverage ratio rules
* Analysts warn of risks to UBS, Credit Suisse
* Finance ministry spokesman says no "concrete action" yet
* UK, US already imposing tougher leverage ratio demands
By Silke Koltrowitz, Oliver Hirt and Laura Noonan
ZURICH/LONDON, Nov 4 (Reuters) - UBS and Credit Suisse would have to hold more capital than international rivals if Swiss lawmakers push ahead with proposals to impose tougher rules on the country's banks to curb borrowing.
Swiss Finance Minister Eveline Widmer-Schlumpf was quoted as saying in a newspaper on Sunday that Swiss banks should be subject to a leverage ratio of 6-10 percent, against the 3 percent imposed on global banks under rules that come into force in 2018.
That would mean Swiss banks would have to hold between 6 and 10 Swiss francs of equity for every 100 Swiss francs of assets they had, against the 3 Swiss francs of equity that would have been required if Switzerland stuck with the international Basel III proposals.
Analysts warned on Monday that by going beyond the global rules, referred to in banking circles as the "Swiss finish," the country's biggest banks could be forced to scale back their activities in key markets like bond trading.
"Over time any such potential move could lead to further shrinkage of the FICC (fixed income, currencies and commodities) division for the Swiss investment banks, especially at Credit Suisse Group," J.P.Morgan Cazenove analysts said.
Shares in UBS were down 3.4 percent at 1107 GMT, while Credit Suisse fell 4.1 percent. Both banks declined to comment.
The leverage ratio is an important measure in the suite of rules international regulators drew up after the 2008 financial crisis with the aim of making banks safer.
"No concrete steps have been taken so far," a Swiss finance ministry spokesman said, referring to the government's previous commitment to examine how its post-crisis banking measures compared with international standards and report back by February 2015 at the latest.
Reporting by Silke Koltrowitz; Editing by Erica Billingham