Factor-based investing

When a portfolio manager decides what to buy, market capitalisation is the default answer. Buy more of the biggest companies. Factor-based investing starts somewhere else.

It picks securities by one measurable trait. That trait might be value, momentum, size, quality or low volatility. The trait is expected to drive returns on its own. Company size does not decide the weight here.

The workbook places this inside Chapter 9's asset allocation decision. It sits alongside strategic and tactical asset allocation. Those two set or shift the long-term policy mix. Factor-based investing instead changes which securities are picked. It also changes how heavily each one is weighted. Rules decide this, not day-to-day judgement.

Two routes into a factor tilt (Chapter 9, section 9.4.4).

• Single-factor investing: a portfolio built on one dominant factor, such as holding only low-volatility stocks.
• Multi-factor investing: combining several factors, for example quality, momentum and value together, to optimise return and reduce risk.
• Smart beta strategies are the index-based route to the same idea; see Smart beta for the factor definitions and the fund products built this way.

Benefits the workbook lists, specific to this decision: enhanced risk-adjusted returns from disciplined factor exposure; diversification, because different factors perform well in different market cycles; a systematic, rule-based process that removes emotional bias; and cost-effectiveness, since factor strategies can offer active-like returns at lower fees than discretionary active management.

Challenges the workbook lists: not every factor works all the time; factor investing needs robust data and is complex to implement, especially for a retail investor working alone; and popular factors can become overcrowded, reducing their future effectiveness.

Illustrative portfolio; the workbook describes the approach qualitatively. A portfolio manager with a ₹5,00,00,000 discretionary PMS mandate is deciding how to build the equity sleeve.

Option A, market-cap weighted. Buy the Nifty 100 in proportion to index weights. Simple, but concentrated in whichever handful of stocks currently have the largest market value.

Option B, single-factor (quality). Screen the same universe for low debt and stable earnings growth, and weight the resulting shortlist equally rather than by size. This tilts the portfolio away from large but highly leveraged names.

Option C, multi-factor (quality plus momentum). Take the quality shortlist from Option B, then further favour the names within it that also show strong recent price performance, combining two factors rather than relying on one.

The manager documents this choice as part of the client's Investment Approach, because factor-based investing is a rules-based method that must be disclosed and followed consistently, not applied selectively trade by trade.

Chapter 9 (Portfolio Management Process), section 9.4.4 (Factor-Based Investing), sits within the asset allocation decision (section 9.4), right after strategic and tactical asset allocation. Expect a question distinguishing single-factor from multi-factor investing, and a question on the benefits and challenges list, especially the risk that a factor stops working and the risk of overcrowding.

• Factor-based investing is a decision approach; Smart beta is the product built on the same factors — the workbook treats smart beta funds as one implementation route, not the whole concept.
• Single-factor uses one dominant characteristic; multi-factor combines several. A portfolio described as "quality and momentum" is multi-factor, not two separate single-factor portfolios.
• It sits between active and passive investing, not squarely in either camp: rules-based like passive, but re-selects securities like active.
• Diversification here means diversifying across factors and market cycles, not across companies within one factor tilt.