Avid Bioservices Inc (CDMO)

[MobyInvestor]

My guess is all of us here wouldn't come close to what one small/medium institutional investor trades in a day.

You guessed correctly as far as how little the retail investor contributes to daily trading volume but, it's not the institutional investors who contribute the most any more:

99 Stocks Account For Half Of Day's Trading Volume As Liquidity Concentrates In Ever Fewer Stocks
http://www.zerohedge.com/article/99-stocks-account-half-days-trading-volume-liquidity-concentrates-ever-fewer-stocks

"The HFT algos are increasingly trading less and less stocks in their attempt to corner just the most liquid stocks. Indicatively, the top 978 names represented 90.01% of total domestic volume, while the remaining 17,597 accounted for just 10% of all dollars traded. Of this, the bottom 12,112 stocks represented less than 0.05% of daily domestic volume."

However, even that explanation is misleading. The following article is probably the best treatment I've seen yet on what is really driving the majority of daily trading volume:

http://www.dailymarkets.com/stocks/2010/04/15/us-stock-market-volume-is-much-worse-than-anyone-realizes/

Regards,

moby