LONDON (Reuters) - A day after paying out $449 million to plug a pension hole in a failed retailer, billionaire Philip Green was given a little financial relief as MySale (>> Mysale Group PLC), the online "flash" sales group he backs, reported a jump in first-half core earnings.

The Topshop owner's family owns a 22 percent stake in the Australia-based MySale, while Mike Ashley's Sports Direct (>> Sports Direct International Plc) holds 4.8 percent, according to Reuters data.

The company, which holds flash sales of fashion, cosmetics and homewares at discounted prices, said on Wednesday it made underlying earnings before interest, tax, depreciation and amortisation (EBITDA) of A$3.0 million pounds in the six months to Dec. 31, up from A$1.8 million pounds in the same period of 2015.

Online revenue increased 19 percent to A$127.1 million as the firm's active customer base also increased 19 percent to 870,000.

"The growth of our underlying EBITDA for four consecutive half year periods endorses our strategic plan and we remain confident in the full year's prospects," said Chief Executive Carl Jackson.

MySale listed on London's junior Alternative Investment Market (AIM) in June 2014 at 226 pence but issued a profit warning the same year.

Over the last year the stock has risen 173 percent. It was unmoved on Wednesday at 120.1 pence, valuing the business at 183 million pounds ($226.39 million).

On Tuesday Green said he hoped his settlement with Britain's pensions regulator would "close this sorry chapter" for pensioners of collapsed department store chain BHS.

($1 = 0.8083 pounds)

(Reporting by James Davey; editing by Kate Holton)

Stocks treated in this article : Sports Direct International Plc, Mysale Group PLC