UPDATE 2-Canadian Western Bank profit slides 15 pct

* Q2 EPS C$0.30 vs C$0.39

* Net income down 15 pct at C$21.6 million

* Says worst is over for margin compression

* Tier I capital ratio at 11.0 percent

* Shares fall 1.7 pct (Adds analyst comments, details, market reaction)

By Andrea Hopkins

TORONTO, June 4 (Reuters) - Canadian Western Bank (CWB.TO: Quote, Profile, Research) said on Thursday its quarterly profit fell 15 percent as declines in the prime lending rate compressed margins, sending its shares 1.7 percent lower.

"Canadian Western Bank's earnings continue to struggle with the severe margin compression it has experienced over the past two years," Dundee Securities analyst John Aiken said in a research note.

"Despite additional loan growth, core earnings have been on a decline, directly from the pressure on its net interest income," Aiken added.