UPDATE 4-Ex-Hochschild Mining exec sells stock, shares fall

* Shares end down 7 pct after news of share placing

* Former non-exec Beeck sells 20 mln shares at 275p each

* Q2 output up 19 pct to 7.2 mln silver equivalent ounces

* Reiterates full-year target of 28 mln ounces

* To post loss of $5.3 mln on forward sales in H1

(Adds placing price, amount of shares sold)

By Eric Onstad amd Victoria Bryan

LONDON, July 15 (Reuters) - A former executive of Hochschild Mining Plc (HOCM.L) cashed in 55 million pounds ($90 million) worth of the company's shares on Wednesday, helping send its stock down after it posted a sharp rise in quarterly output.

Shares in the Latin American silver and gold producer, which had nearly tripled so far this year, closed down 7.1 percent at 279 pence after the share placing by former director Alberto Beeck. Hochschild declined to comment on the placing.