New York Stock Exchange CEO John Thain is doing a bit of back-pedaling on his plan for an earlier start to the Big Board trading day.

On Tuesday, Thain, speaking at the World Economic Forum in Switzerland, told a group of reporters he was considering beginning the trading day at 7:30 a.m. Eastern time -- two hours earlier than the current starting time.

Thain said an earlier starting time was needed to generate more revenue for the NYSE and capture more trading from overseas. The Big Board's also looking to steal back trading volume from electronic exchanges and ECNs.

But by week's end, Thain was moderating his position. In an interview with CNBC on Friday, Thain said he could see opening trading at 8:30 a.m. -- an hour earlier than the current 9:30 a.m. open.

"Eight-thirty is probably a good guess if we had to pick a time," Thain said in the interview. "We haven't decided what we want to do."

Thain's back pedaling on the issue no doubt is a reflection of the chilly response the proposed 7:30 a.m. starting time had received on Wall Street.