Take context from the input text and decide on the accurate relationship between 'Investec' and 'LONDON' from the options provided.
Options: product/material produced, headquarters location, parent organization, position held

LONDON (ShareCast) - (ShareCast News) - Glencore (Xetra: A1JAGV - news ) shares tumbled on Monday on the back of a fairly downbeat assessment from Investec (LSE: INVP.L - news ) , which warned the stock holds little value for shareholders.
headquarters location