South African companies operating in Nigeria are no doubt jittery after two of South Africa's biggest investments in the country faced harsh sanctions from authorities for alleged breaches of regulations.
Last week, MTN, Nigeria's biggest telecoms provider, was hit with a $5.2-billion (about R72-billion) fine from the Nigerian Communications Commission. A day later, the Financial Reporting Council of Nigeria moved against executives of Stanbic IBTC, Standard Bank's Nigerian subsidiary, alleging "financial misstatements" on the part of the bank.
Some watchers have suggested that there's a plot by Nigerian authorities to undermine South African businesses, at a time when both countries are still trying to mend relations.
These relations were impaired by the fallout from two incidents in September last year. First, South African authorities seized $9.3-million in cash being smuggled into the country aboard a private jet. A week later, a church building collapsed in Lagos, killing more than 80 South Africans. The handling of the incident by Nigerian authorities dismayed South Africans.
"It is tempting to see the actions against MTN and Standard Bank's subsidiary in the same week as being part of an anti-South African campaign, but that would be glib," said Dianna Games, executive director of the South Africa-Nigeria Chamber of Commerce. "The issues are very different and affect not only South African companies but other players in each sector."
But she acknowledged that "it is easy for the issues to get clouded by negative sentiments that linger from previous problems between the countries".
Nigeria will continue to be an important market for multinational businesses, including South African ones, faced with market saturation at home.
The IMF's revised 2015 growth projection of 4% for Nigeria, although down from 6.3% in 2014, is still well above the revised 1.4% outlook for South Africa.
MTN played an important part in showcasing the investment potential of Nigeria to the world.
In 2001, defying plenty of expert opinion, it paid $285-million to secure one of three licences on offer in the Nigerian government's reform programme.
At that time, Nigeria was only two years out of the longest spell of military rule in its history, which earned it international sanctions, including expulsion from the Commonwealth.
A decade later, the Nigerian operations had overtaken South Africa's as the most profitable.
MTN's remarkable run in Nigeria, Africa's largest economy, made other South African businesses wake up to the potential of the country's lucrative, if challenging, market.
In 2005, Shoprite took the plunge, opening its first store in Lagos. By 2012, sales of Moët & Chandon champagne in its seven Nigerian stores exceeded sales of the brand in the entire South African market. Shoprite now has 13 stores in Nigeria, and plans to open several more.
Retail brands Pep and Mr Price have followed Shoprite into Nigeria.
Standard Bank acquired a controlling stake in Nigeria's Stanbic IBTC bank in 2007, following a banking reform exercise that reduced Nigeria's 89 banks to 25.
Nigeria's attractiveness lies mainly in its demographics - 170million people, 70% of whom are younger than 35. Were Lagos a country, it would be one of Africa's 10 largest economies.
MTN's importance to the Nigerian economy as one of the biggest corporate taxpayers is one of the reasons the government appears careful to strike a balance between carrot and stick.
A week after the fine was announced, the communications authority approved a five-year renewal, for $94-million, of MTN's original 15-year licence.
The fine has a deadline of November 16, while the licence renewal fee is due by December 31. The timing of the renewal was ostensibly to highlight that MTN's problems in Nigeria are purely regulatory, not political.
Olufemi Awoyemi, CEO of Proshare, a Lagos-based financial information and advisory firm, also dismissed speculation about anti-South African sentiment.
"It's got nothing to do with the origin of the [companies]," he said.
"Nigerian regulators also hit First Bank and UBA with record fines." The two Nigerian banks were fined by the central bank for defying a directive to remit to it all government funds they held.
Awoyemi said Nigeria's regulatory agencies, knowing they are being closely watched by the new administration of President Muhammadu Buhari, are now choosing to sit up.
But none of the recent sanctions by Nigerian regulators has captured the imagination like that levied against MTN, the largest fine in the country - and the global telecoms industry - to date.
"In July, UK company EE was fined $1.5-million, which equates to far less than $1 per subscriber. In Iraq, Zain was fined $100-million in June this year, which equates to about $7 per subscriber," said Thecla Mbongue, senior research analyst at consultancy Ovum. "In the case of the $5.2-billion imposed on MTN Nigeria, we are at a ratio of slightly over $80 per subscriber."
As recently as August, the regulator fined all four leading telecoms companies in Nigeria - MTN , the Nigerian-owned Globacom, Airtel (Indian-owned) and Etisalat (based in the United Arab Emirates ) - for failing to comply with orders to deactivate all improperly registered cards.
The other three complied with the deactivation order.
The Nigerian regulator said the deactivation issue was just one of dozens of "infractions" by MTN. A recent investigative report by a consortium of newspapers has also accused MTN of carrying out damaging "transfer-pricing" practices on profits earned in Ghana and Nigeria - transferring hundreds of millions of dollars to shell companies in tax havens in Dubai, Mauritius and elsewhere, thereby reducing tax liabilities. The company has denied wrongdoing.
Games remained optimistic about business and diplomatic relations between South Africa and Nigeria. "There is not necessarily any cause for South African companies to be overly concerned about their investments in the Nigerian market in this regard," she said .
"The new government [in Nigeria] gives both sides a chance to reset this important relationship and there is work behind the scenes to this end."