It was a terrible year for the chemical industry, which was battered by out-of-control oil prices in the first half of the year and a massive pullback in demand in the second half as consumer spending froze.

Michael Judd, the No. 1 analyst in the sector for the third year in a row, largely dodged the steep collapse with dozens of timely sell and buy ratings on many of the 34 companies he covered. The 47-year-old analyst says he works mainly with hedge funds, and because they trade often, he has to constantly update them with new information.

“It was an extraordinarily challenging year,” says Mr. Judd, who runs his own research firm, Greenwich Consultants LLC, in Rumson, N.J. “I personally was glad when it was over.”

One of his best picks was Georgia Gulf Corp., which makes vinyl compounds and other chemicals, as well as siding, plastic pipes and other construction materials. Although the company was hurt by the construction slowdown, Mr. Judd identified periods of seasonal improvement in which Georgia Gulf’s stock actually rose. It returned 32% during the time Mr. Judd rated it buy and fell nearly 70% when he rated it sell. Overall, Georgia Gulf shares lost more than 80% of their value during the year.