Pensions for top U.S. executive rose by an average of 19 percent last year, and more than 200 officers saw their retirement savings surge by as much as 50 percent, even as their companies stock prices fell, the Wall Street Journal reported on Monday.

Pensions rose as a result of generous formulas and some little-scrutinized techniques, such as changes in age or interest rates used in calculations, the paper said, citing an analysis of filings from 340 Standard & Poor's 500 companies.