Kantar Worldpanel figures for the 12 weeks to 10 June show that Amazon strengthened its market share by 3.2 percentage points, boosted by strong growth in ebook sales and in digital music.
iTunes has also been able to capitalise on the growth of digital music sales, increasing its market share by 2.8 percentage points.
“Amazon has grown its market share considerably since last year and now has a convincing lead over HMV, which has again seen year-on-year losses,” said Fiona Keenan, consumer insight director.
HMV, which secured a crucial lifeline from its banks in January and put its live music arm up for sale in a bid to raise funds, saw its market share slip 0.8 percentage points to 16.6 per cent, though it remains in second place.
However, supermarkets also felt the squeeze. Tesco’s market share has dropped to 10.7 per cent in the past year, while Asda slipped 0.2 points to 8.3 per cent.
Sainsbury’s and Morrisons were the exception to the rule, increasing their share of the market by 0.4 points to 5.3 and 3.3 respectively.
Meanwhile Game, which was bought out of administration by OpCapita earlier this year, shed almost half of its market share over the period, from 7.3 to 3.7 per cent.