Until a few years ago, management trainees picking up appointment letters from state-owned oil companies were reminded of an in-house industry dictum: life is never short of cash up to the level of an assistant manager. The rackets which covertly-and at times overtly-flourished at almost all regional centres of the oil giants have now taken the shape of a Rs 1,500-crore high-speed diesel (HSD) scam. And, according to sources in the CBI which has cracked the nation-wide officer-dealer-retailer network, this figure may be only half the iceberg.