Market always retouches the highs of its first day, always has for 30 years now. This time with the gap it is even more likely to return there and go even lower. Not to mention TNA decay built in. Too many headwinds, Fed saying "adios amigos" sooner than expected, Geitner saying "see ya suckers wouldnt wanna be ya" on February 1st, Europeans lighting themselves on fire cause things are so bad there, the nuclear bomb of the debt ceiling, etc.
Proceed with extreme caution, this thing could be down 10-15% overnight but probably has at best 3 to 6% upside from here before debt ceiling talks tank this market hard like what started end of June 2011 (check the chart, free fall a month and a half or so before the deadline, same time frame as now till mid February...)
It has not happened to me because I do not hold for long periods generally, but you can see it in the charts. Pull up a monthly chart of TZA, it has had to split adjust. Split adjusted, t used to be $2600 at the peak in March 2009, there is no way it would have gone down to $12 from there without decay. Maybe we can use a better term than decay, but regardless it is obviously there.
It is interesting that of the 4 positions you can take with TNA and TZA (long or short), TNA short can work the best of all when market is in trouble because you get the leveraged move down of the 3X component, PLUS that natural time decay of the ETF. Even TZA long in a bear market is not as good because while it gets the 3X leverage up, it loses something in the time decay of the ETF. So TNA might go down at a rate of 3.1 leverage vs TZA going up at only 2.9 leverage (These probably are not the right numbers but it illustrates the point). Actually I guess it works about the same for TZA short in an uptrending market, so that strategy or TNA short in a downtrending market is thus statistically your best bet when the conditions are right. If the headwinds above get traction, that time will be soon for the TNA short.
As an aside, I dont know about other brokers, but I could not find shares to borrow for TNA at Etrade...