The Nigerian naira closed up 0.75 percent against the dollar on the interbank market on Friday, after a surge of dollar inflows from foreign investors positioning to buy treasury bills, dealers said.

The unit closed at 160.90 naira at 1300 GMT, after opening at 160.69 naira on Friday, substantially up on Thursday’s close of 162.10 naira.

Dealers say foreign investors were buying the local unit ahead of a treasury bill auction next week. Nigeria plans to auction 254.61 billion naira ($1.57 billion) in treasury bills with maturities ranging from 3-months to one year on July 12.

It sold a total of 60 billion naira worth in the 364-day bill at 15.6 percent at last month’s auction.

Local units of Total sold $55 million and Chevron sold $38 million, further boosting dollar supply.

“The market is long on the naira because of flows from oil companies and speculation of returns from offshore investors to the local debt market” a dealer told Reuters.

Dealers also said new investors in Union Bank, who bought a 60 percent majority shares in the local lender for $750 million last year, were bringing in hard currency to pay for the stake, thereby providing support for the naira.

The local currency is expected to trade at around 160 levels against the greenback next week, dealers say, if current levels of dollar supply are sustained.

(Reporting by Chijioke Ohuocha and Oludare Mayowa; Editing by Tim Cocks)