Netflix Inc has officially reached 100m subscribers in the second quarter of 2017, adding 5.2m new customers worldwide. Surprisingly, the growth comes outside the US. According to analysts, the new season premiere of House of Cards and the breakout drama series 13 Reasons Why can be attributed largely to Netflix's breakthrough.

Netflix smashed expectations as it garnered 4.14m new monthly subscribers in international markets and 1.07m in the US in Q2 2017. The figures surpassed industry predictions; Wall Street forecast projected 3.2m additional customers worldwide Q2, while analytics firm FactSet predicted 631,000 new customers in the US.

As of June, Netflix has noted for the first time in its history a bigger number of subscribers internationally—52.03m in non-US markets against 51.92m users domestically. In a stakeholder note shared by the streaming platform, it revealed that Netflix has amassed 104m monthly subscribers as of June 2017, stressing that the unexpected growth is due to "amazing content".

In Netflix streaming list, political drama House of Cards now in its sixth season, mystery drama 13 Reasons Why, and comedy drama Orange is the New Black attracted new subscribers in Q2, which is normally a low season for the platform.

House of Cards season 6 pushed the figures further owing to its second quarter premiere rather than its original schedule in the first quarter, according to The Motley Fool. In an interview with CNBC, Netflix co-founder and chief executive Reed Hastings said it had to take more risks in its content delivery this year, citing 13 Reasons Why as an example, but it all paid off very well.

Netflix is turning 20 in August and it has been spending US$6b each year on content to leverage itself as the premier movie and TV streaming service globally. Boosting its efforts, Netflix customises its contents according to markets, even offering various languages support.

On Monday, Netflix stock hit 10.4 percent as it market shares leapt to $178.55 in after-hours trading on 8 June.