Options Clearing Corporation
OCC is the issuer and registered clearing facility for all U.S. exchange-listed securities options, including those traded on the American Stock Exchange, the Chicago Board Options Exchange, the Pacific Exchange, the Philadelphia Stock Exchange and The International Securities Exchange.
http://www.optionsclearing.com/

Canadian Derivatives Clearing Corporation
CDCC is the issuer, clearing house, and hence guarantor of exchange-traded interest rate and equity derivative contracts traded in Canada.
http://www.cdcc.ca/

Clearstream
International clearing and settlement organisation, offering services for domestic and cross-border equities, bonds and investment funds.
http://www.clearstream.com/

CREST
Provides real-time settlement for a range of UK and international shares, UK government bonds and other corporate securities.
http://www.crestco.co.uk/

European Central Securities Depositories Association
Establishing common principles for cross-border activities for efficient and safe securities settlement within the European Union.
http://www.ecsda.com/

Euroclear
The world's largest settlement system for securities transactions, covering both bonds and equities.
http://www.euroclear.com/

Monte Titoli
Provides custody, administration, clearing and settlement services for Italian securities.
http://www.montetitoli.it/

VPC
Clears and settles all trades in the Swedish cash and equity markets.
http://www.vpc.se/

Værdipapircentralen
Clears and settles virtually all securities listed on the Copenhagen Stock Exchange.
http://www.vp.dk/

Norwegian Central Securities Depository
Also provides DvP in NOK in central bank money, and DvP in Euro in commercial bank money.
http://www.vps.no/

Icelandic Securities Depository
The ISD is a registry, a depository and a clearing house for the settlement of equities and bonds in dematerialised form.
http://www.vbsi.is/

Continuous Linked Settlement
Clearing house that eliminates settlement risk in FX, allowing payment-versus-payment in central-bank funds in USD, EUR, JPY, GBP, CHF, CAD, AUD, DKK, SEK, NOK, SGD, NZD, ZAR, HKD, and KRW.
http://www.cls-group.com/

Depository Trust and Clearing Corporation
Provides clearance, settlement and information services for virtually all equity, corporate debt, municipal debt, government securities, mortgage-backed securities, and emerging market sovereign debt trades in the U.S.
http://www.dtcc.com/

Fixed Income Clearing Corporation
FICC was formed by the merger of the Government Securities Clearing Corporation and the MBS Clearing Corporation, and is a subsidiary of the Depository Trust and Clearing Corporation. Site has press notices and clearing statistics.
http://www.ficc.com/

TriOptima
Operator of TriReduce, a multilateral swap tear-up service.
http://www.trioptima.com/

Midclear
Performs clearing and settlement of Lebanese securities.
http://www.midclear.com.lb/

LCH.Clearnet
Formed by a merger of The London Clearing House Limited and Clearnet, LCH.Clearnet clears swaps, equity settlement, energy, bonds and repo, and futures.
http://www.lchclearnet.com/

The Clearing Corporation
Independent clearinghouse for derivatives markets. Features information on history, careers, FAQs, bulletins, member login and services, and contacts.
http://www.clearingcorp.com/

Oesterreichische Kontrollbank
The OeKB handles the clearing and settlement of stock exchange transactions by virtue of a decree of the Vienna Stock Exchange.
http://www.oekb.at/control/index.html

SIS SegaInterSettle AG
Provides the settlement and custody of securities from Switzerland and the world. Swiss central securities depository and global custodian.
https://www.sec.sisclear.com/sec/cm/index.htm