Put options have been recommended as a substitute for price support programs (Gardner, 1977), and subsidized option purchases have received some support in lieu of subsidized insurance programs. Put options are an interesting alternative to price supports because their market-determined price levels allow for flexibility and adjustments to relevant current and expected market conditions. One difficulty with the use of put options as a substitute for commodity price supports is the relative thinness of these options markets for some commodities. Market thinness is defined here as the absence of traders willing to take the necessary opposite position in the market in lieu of a relatively large price premium, particularly for a large number of contracts. We explore empirically how a thin market responds when trading increases as a result of a subsidized put option program. USDA initiated the Dairy Options Pilot Program (DOPP) in 1999 in an effort to provide dairy producers with real-world experiences trading options (Vandeveer et al., 2003). Subsequently, additional rounds of DOPP occurred to give more producers a chance to participate. In total, over 1,300 producers bought 6,500 milk put option contracts through the DOPP program from 1999 to 2002. In contrast, over this four-year period total put options traded at the CME milk futures market totaled over 36,000 contracts. This, the volume from the DOPP program represented a fairly large share of total trading activity in the dairy put options market. An interesting feature of the subsidized milk options program is that dairy farmers may have made relatively little use of commodities markets due to the long-standing dairy price support programs. If this is the case, many of the dairy farmers making use of this subsidized options purchase program would have been relatively uniformed traders. Although DOPP may have increased trading volume, market performance may or may not have been enhanced due to the relative unfamiliarity with options trading by these dairy producers. We define a measure for observed options pricing efficiency using Black's formula in our study of the DOPP program, and statistically evaluate the size of the "error" in options pricing. We find that DOPP trades occurred at statistically significantly higher prices than did other trades, that DOPP volume had a price-reducing effect on other options trades, and that some brokers with large DOPP volume filled these orders at relatively large prices.