If one word dominated South Africa’s markets this week – it was Viceroy.

The short sellers, based in New York, who describe themselves as a “group of individuals that see the world differently”, have been blamed for driving down the share price of Aspen, Africa’s biggest generics drugmaker and that of real estate investment trusts such as Resilient Reit, Nepi Rockcastle, Fortress Reit A and B.

Viceroy Research shot to fame in South Africa over its report on Steinhoff’s accounting irregularities. It then sent the rumour mill to spin when it revealed it would release another report on a South African company in 2018.

Viceroy will be flying out the gates in 2018, and we won’t be slowing down.

We are working on European, South African, and US names for Q1 2018, while continuing to expose $MDXG lies. #staywoke https://t.co/8sUhnLwsgx

— Viceroy (@viceroyresearch) December 29, 2017

The plunge in the share price of Aspen resulted in its CEO Stephen Saad calling for an inquiry into market manipulation. The Financial Services Board’s Tembisa Marele in an emailed statement to CNBC Africa confirmed that it is engaging with the country’s bourse – the JSE – on this matter.

The JSE is “reviewing trading activity and will refer any concerns to the FSB for its consideration. The specific mandate of the FSB in this area, according to the FMA (Financial Markets Act) is to investigate cases of insider trading; price manipulation; and false reporting. This engagement with the JSE will determine what case, if any, the FSB ought to look into,” says Marele .

In response to emailed questions from CNBC Africa Viceroy has hit back:

Q&A With Viceroy

CNBC AFRICA Question: Following news that Viceroy plans to release a report on another SA company rumours have surfaced that it could be Aspen or several listed property companies such as NEPI or Resilient. Our financial regulator and bourse are now investigating alleged market manipulation. How do you respond to allegations that you are behind the market manipulation?

Viceroy Answer: Viceroy encourage [sic] people not to speculate on the identity of any companies we are researching & we advise caution in trading on gossip. Viceroy complies with the laws and have not released research or discussed our focus prior to publication.

We will not provide any further details on our focus as, without our full report, this may constitute market manipulation.

Frankly, the speculation of widespread fraud on the JSE is reflective of a system where regulators are struggling with a lack of funding, allowing bad people to abuse the system, the people and the government. We are most willing to assist regulators in this regard where we can.