Police reports have been filed by angry investors who fear they have lost millions of dollars invested in a local fintech currency trading firm.

SixCapital, or SixCap, promised returns as high as 18 per cent a year but stopped making payouts around June. Investors also had difficulties accessing their performance reports.

The firm e-mailed clients on June 8, saying OCBC Bank told it that its banking accounts could no longer be supported, and it was trying unsuccessfully to open accounts with other banks.

The company was then hit by a surge of withdrawal requests.

In a letter to investors dated Nov 10, SixCap said it had discontinued its two products, Tagg and B'Data, which earn yields for investors through foreign exchange trading.

Investors were told they could expect their principal back "over a 24-month period beginning in the second half of February 2018".

The letter also detailed the abrupt resignation on Oct 9 of SixCap chief scientific officer Abdalla Kablan and 13 of his key IT workers.

SixCap is run by sole owner Patrick Teng Chee Wai.

His son, Paul, who was SixCap's chief investment officer, told The Straits Times he resigned on Nov 1.

One of SixCap's presentation materials states that FX B Share, the predecessor of B'Data, is governed by Singapore law and vetted by law firm Rajah & Tann.

But Rajah & Tann senior partner David Yeow told ST: "The reference to my firm in the attachment was made without prior notice or approval from my firm."

Investors in Tagg and B'Data are now asking how they can recover their money.

Some filed reports with the police and the Commercial Affairs Department last month as they want an investigation into its transactions.

ST visited SixCap's Shenton Way office before noon on Nov 24 but the lights were off and the door locked. A security guard said it had been closed since Nov 20.

It marks a sharp turn of events for SixCap, which once sponsored events hosted by The Wall Street Journal and CNBC, where Mr Patrick Teng would appear as a speaker.