BNP Paribas, the euro zone's biggest bank, posted in-line quarterly results on Thursday, as a jump in corporate financing services offset a continued retreat in trading revenue.

The French lender's third-quarter net income dropped by 4% from a year earlier on a reported basis to 2.66 billion euros ($2.81 billion), almost matching the 2.64 billion-euro analyst consensus compiled by the company.

Group sales over the three-month period ending in September rose by 4% to 11.58 billion euros, slightly above the 11.52 billion-euro consensus.

Under CEO Jean-Laurent Bonnafe, BNP retreated in U.S. commercial lending while bolstering its global investment bank, a move that has benefited the lender as market volatility in the wake of Russia's invasion of Ukraine propelled trading.

It now joins the cohort of peers that have posted steep falls in sales stemming from fixed-income and currency trading, as clients have pared back activity.

"(Third quarter) results were solid with mixed trends at the divisional level," Royal Bank of Canada (RBC) said in an note to clients before the market open.

The broker mentioned lower operating profits in French retail banking, where margins are squeezed by stringent mortgage rules and a government-set rate on the country's most popular savings account.

The bank's shares were down by close to 5% in early Paris trading, with several analysts pointing to the unexpected weaknesses in BNP's retail and consumer finance activities.

BNP's overall revenue from trading fell by more than 9% in the third quarter, as FICC sales (fixed income, currencies and commodities) fell 14.3% excluding the boost from a business the bank moved from equities to FICC.

Germany's Deutsche Bank reported a 12% drop in such revenue for the period, while Britain's Barclays reported a 13% decrease.

The banking industry has been navigating a complex backdrop of quickly rising interest rates, which have bolstered lending income, while an uncertain economic outlook and geopolitical upheavals cloud prospects.

BNP's global banking business, which comprises bond issues, syndicated loans and cash management, saw sales jump by about 20% in the third quarter, offsetting the downturn in trading.

BNP set aside 734 million euros for credit losses in the third quarter, below the 815 million euros expected by analysts. The group's operating expenses, up 3.4% over the period, grew at a slower pace than sales, also supporting earnings.

The group posted a 12.7% return on tangible equity (ROTE), on course to meet a target it set of 12% by 2025.

It also completed more than 85% of a 5 billion-euro share buy-back programme for 2023, equivalent to about 7% of its market capitalisation.

Proceeds from the sale of Bank of the West, BNP's former U.S. retail subsidiary, financed the buy-back. ($1 = 0.9463 euros) (Reporting by Mathieu Rosemain; Additional reporting by Augustin Turpin; Editing by Anousha Sakoui and Elisa Martinuzzi)