What happened

Shares of JPMorgan Chase (NYSE:JPM) jumped nearly 15% last month, according to data from S&P Global Market Intelligence, following the bank holding company's strong first-quarter results.

So what 

The largest U.S. bank by assets saw its revenue and earnings per share rise 5% and 12%, respectively, to $29.9 billion and $2.65. Both figures came in well above Wall Street's estimates.

JPMorgan Chase is enjoying broad-based growth. The company grew its deposit base by 3%, while its retail loan portfolio increased by 4%. Credit card sales volume rose by 10%. Advisory revenue jumped 12%. Debt underwriting leapt 21%. And investment banking revenue surged 44% to a record high. 

Rolls of dollar bills rising in a stair-step manner

Image source: Getty Images.

Better still, JPMorgan Chase is achieving this impressive growth while keeping a lid on expenses. The company's overhead ratio -- essentially, non-interest costs divided by total revenue -- actually declined to 55% from 56% in the year-ago quarter.

Now what

JPMorgan Chase is one of the best-run banks in the world, with consistently strong returns on equity despite its conservative leverage ratios. The financial giant's tremendous scale and innovative culture should continue to serve it well in the coming years. And as the nation's leading bank, JPMorgan Chase is well positioned to profit from a strong U.S. economy.

Yet with its stock currently trading for less than 11 times forward earnings estimates and about 1.5 times book value, JPMorgan Chase's competitive strengths and solid growth prospects do not appear to be reflected in its share price. As such, even after April's gains, its stock remains perhaps the best buy among the major U.S. banks.