This is the time of the year when building owners and managers should review their tax bills. Most cities and towns are sending the bills prior to December 31st. Owners and managers who have determined that their assessments are too high should take the following steps: (1) File an application for abatement with the local assessors on time; (2) Pay the tax on time; and (3) Appeal to the Mass. Appellate Tax Board on time. A taxpayer must file the application for abatement with the board of assessors within 30 days after the tax bill is mailed. The key is to do each of the foregoing steps on time. If they are not done on time, the taxpayer loses any rights he may have to an abatement. Taxpayers should use the time prior to receiving the tax bill by reviewing the assessment to determine if it is fair and reasonable. The valuation of commercial prop. is usually based upon an analysis of income and expenses. Accordingly, assessors ask taxpayers to fill out and send to the assessors an income and expense form. The authority of the assessors to ask for this info. is in Chap. 59 Sec. 38D of the Mass. general laws. Taxpayers often are reluctant to submit this info. to the assessors. However, it is essential that this info. is provided. Even with the income and expense data, assessors sometimes use the wrong methodology in valuation of commercial props. For this reason, owners should retain a lawyer and an appraiser experienced in this field early in the process. There's been a downturn in the R.E. markets and an increase in vacancies. Taxpayers have the burden of proving that buildings have a lower value than that assessed. This should not discourage taxpayers from filing an application for abatement with the local assessors. Saul Feldman is an attorney with Feldman & Feldman, P.C. Boston. Saul Feldman