Jan 7 (Reuters) - The Swiss National Bank"s foreign exchange reserves rose in December, data showed on Friday. The SNB held 944.532 billion Swiss francs ($1.03 trillion) in foreign currency at the end of December, compared to 921.690 billion francs in November, revised from an originally reported 1006.404 billion, preliminary data calculated according to the standards of the International Monetary Fund showed. ($1 = 0.9211 Swiss francs)