The grade and price offers should be submitted on Tuesday and Thursday, respectively. Offers will remain valid on Thursday. IOC typically buys Nigerian light crude by issuing tenders several times every month. The latest tender, its first for May, came out with West African still trading for April loading. "The timing of the tender is not good. A lot of April cargoes have remained unsold," one trader said. Traders said as much as two-thirds of April loading Nigerian crude was still looking for buyers. Some traders said the such a forward tender favours oil majors who have equity in those cargoes while independent traders often have to negotiate their allocations.