An exchange traded fund designed to amplify the moves of red-hot US tech stocks has just suffered its worst ever week of outflows, suggesting that investors are growing wary of highly stretched valuations.
Investors pulled $491m from the ProShares UltraPro QQQ ETF last week in the biggest weekly
```
Members Only
Login or create an account to continue
This article is available to registered BusinessDay readers. Please login if you already have an account, or create a new account to continue reading.
New to BusinessDay? Register now and start reading.
```