Swiss bank Credit Suisse Group has reported a huge jump in first-quarter profits compared with a year earlier, when it booked significant charges to its own debt.

Switzerland's second-biggest bank posted a profit of 1.3 billion Swiss francs ($1.37 billion).

This was up sharply from the 44 million francs in the first quarter of 2012, when it booked a loss of 1.6 billion francs on its own outstanding debt and paid out higher bonuses.

Net revenue rose 6% to 7.2 billion francs.

The figures show "positive momentum" based on a transformed business model, the bank said in its statement.

"The first quarter of 2013 shows that the strategic measures we have successfully implemented since mid-2011 are effective in bringing results to the bottom line on a consistent basis," chief executive Brady Dougan said.

The bank, based in Zurich, said the results for the three months from January to March showed "high returns, strong client franchises, reduced cost base and lower risk-weighted assets."

Like its Swiss peer, UBS, which is Switzerland's biggest bank, Zurich-based Credit Suisse has been reducing its riskier investment banking activities at a time when Europe's economy is hurting.

The bank's quarterly report also showed further cutbacks in its staff, to 46,900 people, down 4%from 47,400 a year earlier.

Credit Suisse said earlier this week that it was selling its private equity business, Strategic Partners, which is based in Zurich, to New York-based Blackstone Group for an undisclosed amount. Strategic Partners manages $9 billion in assets and buys stakes in other private equity funds.

The Zurich bank agreed last month to buy Morgan Stanley's wealth management unit, with $13 billion in assets under management, to expand in Europe, the Middle East and Africa.