How do the numbers under these titles help me in deciding weather to buy or not
The best bid and ask (lowest ask/highest bid). The values at the top of your DOM display.Could you clarify:
“Inside Bid-Ask”
There is spoofing at all levels within the DOM. A MM might show size on the Bid a couple of levels down to indicate Buying intent/pressure. As the instrument moves up in anticipation (as others get on board and start buying, thinking they're ahead of size) the MM will switch to Ask, or even just pull their Bid if they've gone through an ECN to sell through the back door.“MMs play the inside (and the depth too)”
When you're looking at your planned position size you need to check what level(s) you're likely to get filled at if at market and as importantly, what sort of depth there is on the other side to accomodate your quick exit once you're in if you're wrong. e.g. No point taking on 5000 if you'd need to cover 10 deep to get that many off on the exit with a vertical spread of $1.50 to do it. You're estimating your exit slippage and taking that on as part of your entry risk assessment.“look at the depth for Bid and Ask and look at the vertical spread”.
I've just noticed I am now a "Veterean Member". What does that mean?
This simply isn't true. On the most volatile stocks you'll see this switch back and forth a dozen times in minute in heavy trading. Plus, for the reasons I mention above, you have to take into consideration the size you see may be the size 'they' want you to see, or not.You should use cumulative depth volume as a leading indicator! Whenever you see one side of the market is larger, that is where price will most likely go. Most people think it's the other way round, thus lose.
This simply isn't true. On the most volatile stocks you'll see this switch back and forth a dozen times in minute in heavy trading. Plus, for the reasons I mention above, you have to take into consideration the size you see may be the size 'they' want you to see, or not.