* SEC cites insider trading, ownership issues
* Company gets notice, regulator orders audit
* Oando has gained 27 pct this year (Adds comments from Oando, bullet points, background)
By Chijioke Ohuocha
LAGOS, Oct 18 (Reuters) - Nigeria's Securities and Exchange Commission (SEC) said on Wednesday it had ordered the suspension of Oando shares, citing concerns about possible insider trading and the oil company's shareholding structure.
The SEC ordered the Nigerian Stock Exchange to implement a 48-hour suspension of Oando's shares after which it would implement a price freeze until further notice.
Oando, which is also listed in Johannesburg, said it had received a communication from regulators on the share suspension, adding that it will state its position as soon as possible.
Its shares, which have gained 27 percent this year after a sharp fall last year, last traded at 5.99 naira in Lagos.
The regulator said it had carried out a comprehensive review of Oando after it received two petitions and found related party transactions were not conducted at arm's length and discrepancies in its ownership structure.
A company source said the petitions centred around the ownership of some Oando shares bought through an investment vehicle at the time the company bought ConocoPhillips' Nigerian business for $1.65 billion in 2014.
"The commission notes that the above findings are weighty and therefore needs to be further investigated. After due consideration, the commission believes that it is necessary to conduct a forensic audit into the affairs of Oando Plc," the SEC said in a statement.
It said a team of auditors, lawyers, stockbrokers and share registrars would conduct the forensic audit on Oando to ensure independence.
Last month Nigeria's lower house of parliament gave the SEC two weeks to disclose the results of its investigation into the oil firm.
The regulator has been investigating Oando's shareholding structure but had not published its findings and last month allowed the company to proceed with its annual shareholder meeting. (Additional reporting by Alexis Akwagiram; editing by Jason Neely and Adrian Croft)