Hi mbondy,
I guess you were referring to S&P-500... Yes, you are correct, LS have increased their net long positions, but (!) let's not forget about the important fact --> LS are the ones pushing the trend, but as they reach an extreme position /as the one now/, obviously we can expect the Trend to change.
So the question you should be asking is: Ok, LS are buying buying and buying... for how long can this go on? COT history (in case of S&P it is 22 years) shows that Large Speculators have never held sooooo much contracts LONG, they have never been as bullish as they are now. So question is: should we expect this buying power to stay as it is?
COT history show that at the end of a major trend, major participants of the markets are usually holding extreme amount of contracts in one direction --> this is called a COT Extreme.
So to answer your qestion "Where are the bearish signals that you're suggesting?" --> From the facts above.
I hope I could help you clarify all this.
All the best,
Dunstan