J. H. Cline in the 2007 edition of his SLQ reference – the final paragraph on page 174 of that book reads:

The 1927-S has such a low mintage that there are few Full Heads in existence. If all Full Heads had been withheld from circulation, it would still have been the scarcest S mint of the entire series excluding of course the 1918/7-S. I give the 1927-S a liberal estimate of one percent struck with Full Heads. That would leave about 3,900 that struck with Full Heads. This number decreases considerably because, indeed, some did make it into circulation. Your author would rate it five times rarer than the 1916 in Full Head. With that said, the present price for a 1927-S FH is not in line with the real scarcity of the coin. In the 45 years your author has collected and admired these coins, the ratio I have observed is at least one 1927-S to twenty-five 1916s with Full Heads.

The example to the left was sold by Stack's Bowers Galleries in the November 2010 Baltimore Auction, where it realized $149,500.