Securing a private letter ruling from the IRS, if available, is often an excellent way to proceed in regard to a substantial tax transaction since such a ruling, essentially, provides insurance that the IRS will accept the taxpayer's reported tax treatment of the transaction. In the partial liquidation area what is the minimum contraction (expressed in a percentage, but without using the percentage symbol) does the IRS require the expected contraction of the business (as represented by the net fair value of assets, gross revenue and the number of employees) to be in order to consider issuing a private letter ruling?