On 16 January 2019, the Federal Council decided to put the tax proposal and AHV financing (STAF, formerly SV17) to a vote on 19 May 2019, provided that the referendum was successful.
According to a press release issued by the Federal Council on 16 January 2019, the bill on the Federal Act of 28 September 2018 on Tax Reform and OASI Financing (STAF) (BBl 2018 6031) will be put to the vote on 19 May 2019. The vote is subject to the condition that the referendum against the bill is successful. The referendum deadline expired on 17 January 2019.
The Federal Chancellery (FC) has not yet issued an official statement on the successful outcome of the referendum (cf. the FC's media releases). However, according to current media reports and a media release from the Referendum Alliance, over 55,000 signatures have been submitted against the Federal Law on Tax Reform and AHV Financing (STAF). The referendum would therefore have been successful.
The Federal Department of Finance (FDF) has outlined the procedure up to the entry into force of the STAF - including a possible referendum vote - on the FDF website (the graphic representation as PDF is available here).