Updated from 3:16 p.m. ET to include additional information on the performance of the major U.S. equity indices in the past week and year-to-date. NEW YORK ( TheStreet) -- With every passing positive session, it becomes more difficult to question the legitimacy of the current rally in stocks. Maybe it's appropriate now to switch gears and think about what could come along and derail this train. A weak read on consumer sentiment aside, few would argue the economy isn't on reasonably solid footing right now with the employment picture improving, inflation in check, and even housing percolating a bit. The Federal Reserve acknowledged as much earlier this week, sparking Tuesday's surge in the major U.S. equity indices that's led to all these big, round numbers being conquered. "Information received since the Federal Open Market Committee met in January suggests that the economy has been expanding moderately," the latest statement began, omitting a reference to "slowing global growth" that was included in January. "Labor market conditions have improved further; the unemployment rate has declined notably in recent months but remains elevated. Household spending and business fixed investment have continued to advance." So what's to worry about then? Higher gasoline prices could be problem, potentially prompting consumers and businesses to slow spending. Greece is out of the woods for now but it's not like the region's problems are solved or the prospect of a recession in Europe is off the table. The thing is though, these factors are well known and investor appetite for equities hasn't slowed nary a bit. What may be more helpful is to get a bit more basic, and ask whether corporate earnings growth in 2012 is going to support continued gains for stocks. UBS, which has a year-end target of 1475 for the S&P 500, weighed in on the subject earlier this week. "