THE RELATION BETWEEN TAX RATES AND PRE-TAX RETURNS DIRECT EVIDENCE FROM THE 1981 AND 1986 TAX RATE REDUCTIONS

This study documents one effect of the theory of implicit taxes, providing evidence that a change in the tax rate results in a change in pre-tax returns. Yield spreads of pairs of Treasury bills maturing in the last week of December and the first week of January are examined. Year-ends not affected by rate changes show a significant positive yield spread between these pairs of bills, reflecting an upward-sloping yield curve. However, for year-ends coinciding with the tax rate reductions of 1981 and 1986 there is a significant negative yield spread between these pairs of bills.