Pension system rules are hard. There are separate funds, separate interest rates assumed for collections and payouts, even rules about what kinds of things the fund can invest in. This bill lifts restrictions on investing in Northern Ireland, while the funds’ interest-rate assumptions will be lowered by about one-quarter of 1 percent (from 5.5 percent to 5.25 percent, in the case of “accumulation of member contributions,” and from 8 percent to 7.75 percent for “regular interest”). Regular interest is the rate of return on investments the fund managers assume they’ll get. The higher the assumption, the less money the workers and management have to pitch in every year. So lowering the assumption will bring more realism to the fund and also require bigger cash contributions to keep them solvent.