MUMBAI: IndiGo, India’s biggest carrier by market share, posted an over fourfold increase in its net profit for the financial year 2014-15, as a fall in fuel prices and interest income from its surplus cash aided operations. The airline posted a record net profit ofRs 1,304 crore for the year ended March 31, compared with Rs 473 crore a year ago.Its revenues rose 25 per cent to Rs 14,320 crore from Rs 11,447 crore in FY14. The carrier filed its results during the day with India’s aviation regulator, the Directorate General of Civil Aviation IndiGo’s fuel expenses rose just 4 per cent to Rs 5,748 crore during the year. It expanded its capacity by 18 per cent to 35.5 million available seat kilometres. The airline’s average yield for the year came in atRs 4,033, compared with Rs 3,815 in the previous year."Besides benign crude oil prices which have fallen by 40 per cent to $45 per barrel in the past one year, we have benefited from combination of revenue-enhancing factors. Enhanced capacity, which ensured higher number of planes, lower costs and better yield arising out of rising passenger traffic have played a crucial role in driving profits for us," said the airline’s president Aditya Ghosh.A strong push to its profit came from its interest income of Rs 279 crore from its investments in fixed deposits, up 50 per cent on year.IndiGo has been profitable for the last seven of the nine years of its existence, due to a impactful expansion plan, a tight control on costs, mammoth plane orders which helped it wrest discounts on expenses such as maintenance and lease rentals.For FY15, the airline’s profit before tax (PBT) stood at Rs 1,847 crore, which is close to four times its PBT in FY14.IndiGo is readying itself for aRs 2,500-crore initial public offer (IPO) later this year or early next year, aiming for a valuation close to $4 billion, close to eight times of the market capitalisation of its near rival Jet Airways. Many analysts have called the figure ‘ambitious’.The company has given dividends amounting to Rs 3,500 crore to its promoters between FY11 and FY16. Also, between FY15 and FY16 itself, the airline paidRs 2,083 crore to its promoters. Given its brimming cash reserves, some analysts have questioned its need for an IPO and also said it may face "problems of plenty"."Typically, a listed company will be able to access many more funding avenues. We feel we are entering the capital market at the right time considering the fact that passenger traffic is rising and crude oil prices are at attractive levels. Today, we are standing on a springboard and we generate a lot of cash, which augurs well for us," said Ghosh.