The number of BSE 500 companies that have crossed a debt-default probability threshold has trebled since the beginning of the year. Vodafone Idea, Dewan Housing, Bombay Dyeing , Srei Infrastructure, Jet Airways , Indiabulls Real Estate, Indiabulls Housing Finance, & Reliance Capital are among 77 companies that have a default risk probability of more than 0.52 per cent compared with 24 at the beginning of 2018, according to Bloomberg data. The stocks of these companies have fallen by an average 49 per cent this year compared with a 5 per cent drop in the BSE 500 index.Globally, investors stay away from companies with a 0.52 per cent chance of defaulting on debt in the next 12 months. The probability is computed by Bloomberg using its proprietary risk model based on parameters such as share price, market capitalisation, share price volatility, short-term debt, longterm debt, interest expense and adjusted cash flow from operations.The market has been on the edge over default worries since September when Infrastructure Leasing & Financial Services (IL&FS) was unable to make debt payments. Such concerns hit investor sentiment on non-banking finance companies (NBFCs) such as Dewan and Indiabulls, which have denied being under pressure on this front. The government has been pushing the Reserve Bank of India to ensure adequate liquidity for NBFCs affected by asset-liability mismatches stemming from borrowing through short-term instruments and lending for longer tenures.The 77 companies have a market capitalisation of Rs 6.75 lakh crore, accounting for about 4.5 per cent of the total. There are 37 companies in the sample with a market capitalisation of more than Rs 5,000 crore and 47 belong to sectors other than banking and finance.Excluding financial companies, the total debt of companies with a high default risk probability dropped to Rs 6.65 lakh crore in FY18 , compared with Rs 7.1lakh crore in FY16.Their interest coverage, or ability to repay debt, improved to 1.87 from 1.43 in the same period.The default probability of these prominent companies has shot up in the past six months as their stocks have dropped. For instance, the default probability of Vodafone Idea has surged to 4.99 per cent from 0.4 per cent in March. On the other hand, that of Jet Airways eased to 3.2 per cent after hitting a record of 5.6 per cent in October following the Tata Group ’s stated interest in acquiring a stake in India’s second-largest airline.