The recent joint proposals from FASB and IASB to eventually overhaul lease accounting rules would most impact retailers, according to an in-depth report from Credit Suisse Securities.

The Swiss investment bank estimates off-balance-sheet lease liability for the S&P 500 companies is at least $549 billion. It figures two industry groups--Food & Staples Retailing and Specialty Retail--account for 25 percent of the total.

This means the potential accounting changes could have huge ramifications for the CFOs at those firms. "If bringing leases on balance sheet were to change investors' and creditors' opinions about corporate leverage and risk, stock prices and financing costs could change as well," Credit Suisse warns in its report.

It also speculates that the changes might also push companies toward shorter term leases or leases without renewal options to reduce reported leverage, exposing them to increased market risk.

The two accounting Boards want to eliminate the concept of operating leases, which are currently accounted for off-balance-sheet, and apply one accounting model to all leases, Credit Suisse told its clients.

It elaborates that under the new model, the "right to use" the leased asset would appear on the balance sheet of the party leasing the asset as an asset and separate from owned assets within Plant, Property & Equipment (PP&E), and the obligation to make future lease payments would be reported as a liability. The upshot: All leases would finally appear on the balance sheet.

This is not a bad thing, the bank told its clients. Given the significant amount of balance sheet lease assets and liabilities along with lease financing costs currently buried in operating income for the lessee, it asserts that the accounting is flawed. It says the financial statements simply don't reflect the underlying economics of most lease transactions.

The bank said that among the S&P 500 companies, it found 34 companies where the off-balance-sheet operating lease liability was more than 25 percent of market cap. In fact, for 14 companies, it is more than 50 percent of their market capitalization.

The 14 companies are Office Depot, Walgreen, Supervalu, Edison International, Sprint Nextel, Abercrombie & Fitch, Whole Foods Market, CVS Caremark, Kohl's, Sears Holdings, MetroPCS Communications, Best Buy, Tesoro and FedEx.