AM Alpha has sold a Sydney office asset for almost double its 2011 purchase price.

The Munich-based family office said it sold the prime building, in which it held a 75% stake, for AUD112.3m (€79m).

AM Alpha bought the property, at 309 George Street, in October 2011 for AUD68.75m.

The asset, in Sydney’s central business district, includes retail and office space.

AM Alpha said it refurbished the building since taking ownership in a joint venture with Abacus.

Tan Yeow Beng, managing director at AM Alpha in Singapore, said: “We have had a positive experience investing in Australia, a transparent market of depth and liquidity.

“Australia offers diverse opportunities across different cities and asset classes.”

Beng said AM Alpha would continue to focus on “key Australian cities”, as well as other Asian gateway cities in Japan, Greater China and Singapore.

“As part of our investment strategy, we are open to engage with joint venture partners for interesting risk-adjusted value-propositions.”

In 2013, AM Alpha sold a trophy asset in Berlin’s Friedrichstrasse to a Swiss investor and sold an office property in Dublin for €49.3m one and a half years after having bought it for €36.5m.

The firm, which manages a $2.5bn (€2.2bn) portfolio in Europe and the Asia-Pacific region, has also sold residential properties across Berlin for more than €50m.

AM Alpha’s transaction volume last year totalled more than €600m, with a sales volume of €480m in Dublin, Munich and Berlin and acquisitions of €120m in Amsterdam and Munich.