At a time when scores of companies are freezing pensions for their workers, some are quietly converting their pension plans into resources to finance their executives' retirement benefits and pay.

In recent years, companies from Intel Corp. to CenturyTel Inc. collectively have moved hundreds of millions of dollars of obligations for executive benefits into rank-and-file pension plans. This lets companies capture tax breaks intended for pensions of regular workers and use them to pay for executives' supplemental benefits and...