The premium for storing U.S. crude oil for one year over crude for immediate delivery has grown to its widest since mid-August, Reuters charts showed on Friday. The December 2016 contract for the U.S. West Texas Intermediate (WTI) was trading at nearly $7.50 a barrel above December 2015 <CLZ5-Z6> by 9:54 a.m. EST (1454 GMT), the widest premium since Aug. 18. Traders attributed the spike to a rush to store oil as U.S. crude’s fundamentals in the near-term worsen from rising inventories.