NEW YORK (CNN/Money) - Citigroup Inc. posted improved first-quarter earnings Monday that beat Wall Street expectations.

The nation's largest financial services company earned $4.1 billion, or 79 cents a share, from continuing operations, up from $3.5 billion, or 66 cents a share, on the same basis a year earlier. Analysts surveyed by earnings tracker First Call forecast earnings per share of 77 cents.

The company saw gains across its various units. Income from its consumer business, including retail banking and credit cards, increased 26 percent, its corporate and investment banking business income rose 22 percent and its investment management units saw a 10 percent increase.

Revenue increased 4 percent to $18.5 billion, as gains in retail banking, credit cards, life insurance and annuities helped overcome weakness in the company's equity trading unit. The company also saw provisions for loan losses decline $506 million from the year-earlier period, due primarily to the absence of $644 million in writedowns and additional reserves taken a year earlier related to Argentina.

The company benefited from low interest rates in the quarter, which not only drove demand for residential mortgages and other lending, but also produced record income from the company's fixed income unit.

Shares of Citigroup (C: Research, Estimates), a component of the Dow Jones industrial average, gained 65 cents to $38 in pre-market trading Monday following the report. Its shares closed up 40 cents to $37.35 in trading Friday.