The company - which was the first derivatives trading company to set up in Wales - will create 132 new jobs, the majority being graduates from Glamorgan and Cardiff University Trading Floor Schools, along with students from Swansea University.
At the end of their recruitment drive, OSTC's office in Swansea will be their largest.
The project is being supported with financial assistance from the Welsh Government which helped secure the project for Wales against other locations that were under consideration.
This expansion follows on the heels of another project announced earlier this year and supported by the Wales Economic Growth Fund that will see OSTC create 19 jobs as a new team is set up to specialise in power trading markets.
On a visit to OSTC today (Thursday July 12 ) Business Minister Edwina Hart described the expansion as a boost for Wales' Financial and Professional Services Sector, one of nine key sectors identified with high growth potential.
Congratulating OSTC Mrs Hart said:
"This is a major expansion project that will help establish Wales as a growing centre for this highly specialised sub sector. It will also create a significant number of skilled jobs that will enable graduates to remain in Wales to follow their careers and also attract the brightest talent to Wales.
"OSTC Wales has grown significantly since it began trading in Swansea in 2009 and I am pleased to hear it is working closely with Welsh universities and able to recruit the high calibre graduates it needs to support business growth."
Michael Shirley, Managing Director of OSTC Wales said:-
''OSTC prides itself on being a leader and employer of choice in our industry. OSTC is a global leader in derivatives trading, with 12 offices in the UK, Europe, Asia and North America, OSTC specialises in maximising the potential of every trader and trading opportunity in its chosen markets. This has been highlighted recently by OSTC Wales being awarded the Investors in People Gold award.”
OSTC Wales has a track record of recruiting and training talented graduates to trade the financial markets using specialised and bespoke electronic software systems.
OSTC Wales was formed as a joint venture between Kondor Trading Ltd and OSTC Ltd. OSTC is now a significant participant in the world of soft commodities such as cocoa, coffee and sugar, energy markets, agricultural markets and fixed income markets.
OSTC Wales recruitment for their expansion will start in 2013 and will see graduate intakes each February and September through until 2017.